P

prkaye

Well Known Member
I don't know anything about turbo-chargers... are they something that can be "added-on" to an existing engine? For example, if I put an O-320 on my plane, and then later on decide I want to fly higher, can I simple slap a turbo-charger in there, or would this constitute a serious modification requiring taking the engine off, etc ?
 
Its a serious mad

Serious as in if you get it wrong you will blow your engine up!...Or destroy it through detonation.

I would only do this if there was a proven bolt on kit out there that already has all the engineering done.

Expect your engine to have a shorter life in any case.

I'd go the simpler route and bolt on an (I) O360.

Frank
 
You probably wouldn't have to remove the engine but you will need to keep some things in mind:

The turbo will have to be low mounted so you will need a scavenge pump to return the oil to the sump.

It needs to be intercooled so you need a place to mount that plus inlet and exit ducting for it.

The turbo needs to mounted solidly, you can't hang it off .035 or .049 exhaust tubing. You need slip joints on the header tubes. You will need space for a 2.5 inch exhaust pipe to exit the cowling.

You should have a wastegate. If separate type, this needs its own exhaust pipe also.

This will add a minimum of 30 pounds to the firewall forward weight. If you have a Hartzell C/S prop, C of G will be a concern probably.

If you are carbed and blow through, you need a boost referenced fuel pressure regulator to maintain FP differential above boost pressure and the pump to feed it plus a way to vent to bowl to boost. If you are injected, mods to your control unit may be required.

If your CR is below 8 to 1, you can probably safely normalize on 100LL. If you plan to boost more than a couple psi, you need to watch spark timing.

Cooling requirements will be higher due to the higher thermal load. Watch CHTs and oil temps.

You must watch the TAS at high altitudes and flutter margins.

These are all reasons why you don't see too many turbos on RVs.
 
Add this one:

If you are injected, you will have to change injector types to include an upper deck reference line.


This is no small feat of engineering. It took GAMI/TAT almost two years to properly engineer the turbo for the Cirrus. It was FAA Certified yesterday! And, remember, they know what they are doing. They already have turbo STCs on other airplanes.

Walter
 
Supercharger

Talk to Jeff Neilsen, if you can catch him. His supercharged RV-6 is unbelievable.

Miller McPherson
RV-6 770+ hours
 
There's a fella in Texas with a Turboed RV8. He calls it Grezdlitnin. There's a sport pilot article on it somewhere. He's also been to LOE a few times.

Guy
 
A 160 hp RV-9A has a 24,500ft service ceiling, sans turbo!

prkaye said:
I don't know anything about turbo-chargers... are they something that can be "added-on" to an existing engine? For example, if I put an O-320 on my plane, and then later on decide I want to fly higher, can I simple slap a turbo-charger in there, or would this constitute a serious modification requiring taking the engine off, etc ?
Click to expand...
By the way your phrased "slap on a turbo-charger" and the fact your building a RV-9A, my guess is you have not flown a turbo charged plane or may be even a RV yet? I don't know.

Besides $$cost$$, weight and complexity, to take advantage of turbo charging you need to fly at high altitudes, which require you suck O2, all the time. Do you have experience sucking O2 for hours? It's not fun, dries the nose out and you need to fill tanks, etc. etc. Than there is Vne. You can fly higher and faster but you will run into Vne, which you can consider is based on TRUE AIRSPEED, not indicated. Van publishes a single Vne indicated. However the "real" Vne drops about 2 mph indicated for every 1000 ft altitude.

Hot engine? As you climb the air is thinner. Thinner air means less cooling. Compressing induction air (turbo) and maintaining higher HP at altitude means a HOT running engine. This is why they have inter-coolers. When you compress air you heat it. You are stuffing this pre-heated air into an engine that is getting less cooling air. An inter-cooler BTW adds even more complexity, weight and cost. Bad news is cowls on RV's are small and tight, for speed, right. There's not a lot of room for the turbo, much less an inter-cooler. RV engines are also not cantilevered off the firewall far, meaning its crowded behind the engine as well, where some aircraft stuff their turbo.

Have I convinced you? Look if you want extra altitude performance, start with more sea level HP and keep your plane light. I don't know much about the new IO340 (170HP) engine, but it may be a good match. It keeps the weight down, gains a little HP boost, both a win win. It would allow higher service ceiling without running dangerously up against the Vne, but you still may have to watch it.

PAIN IN THE BACK SIDE
With a normally aspirated (not turbo-ed) engine the HP drops to protect you from exceeding Vne. There are some good threads on this and Van has published his admonishment against Turbos in RV's. Can it be done? Yes. Is the RV-9A a good match? No, of all the RV's it is the least suitable in my opinion, for one weight. I have flown several Turbo planes as a commercial pilot, flight instructor and they are pain's in the back side. They seem to be in the shop a lot. Fortunitly I did not have to pay for maintenance since I was being paid to fly them. The clubs C210T (turbo) was in the shop every 50 hours for major work on the exhaust or inter-cooler.

HOW HIGH DO YOU NEED TO FLY?
The RV is plenty fast and efficient with out a turbo. That is the beauty of it. Trust me flying real high where you can't see much loses its thrill after a while; RV's are plenty happy at sufficiently high altitudes. A 160 HP RV-9A already has a service ceiling of 19,000 (gross wt) and 24,500 ft (solo). Now service ceiling is NOT a practical altitude to fly at, you are just hanging on the prop, but 5 or 6 thousand feet lower is doable on a standard day. So you can easily cruise at 13,000-14,000 feet any time at gross weight and up to 18,000 feet solo! :eek: You know you have to be on a IFR flight plan above FL180. Above 12,500 to 14,500 ft for more than 30 min you need O2. Above 14,500 you need O2 100% of the time. So the RV-9A is no slouch in altitude performance. SO if you want to suck O2 than you can still climb to nose bleed altitude without a turbo. The 170HP IO340 would add slightly to the altitude performance. The RV-9 has a good wing for altitude, but its weight. Don't make your RV heavy. You will regret it. The lighter the more "RV like" your plane will fly. Weight affects takeoff distance, climb rate, max altitude and landing distance. Also the handling is heavier and not as nice. A turbo does nothing super practical for you in a RV, but can and has been done a few times. Your choice. Good luck.
 
Last edited:
How much HP do you really need in an RV-9a? Adding more HP doesn't add a lot of speed, at least not as much as a bit of streamlining might, but it can increase climb rates and use a lot more gasoline in the processes.

If you want much more than the recommended 160 HP and want to keep weight close to Vans recommendations, you certainly do not need a super/turbo charger to achieve it. Turbos do give a bunch of power, but they also add a lot of potentially damaging heat that is more difficult to dissipate high up in thin air, especially with air cooling.

My recommendation if you are serious about needing or wanting more power, consider a Rotary (Renesis) engine; around 200 naturally aspirated HP at the O-320's weight (around 350 lbs fwf), and gain all the other inherent rotary advantages along the way (durability, reliability, low costs, smoothness, etc). Rotaries have the best power:weight Ive seen so far in a small package.
 
No turbo...too muc weight and complexity. :rolleyes: :rolleyes: :rolleyes:

I know!!! lets add a car engine....thank goodness we kept it simple.

And, mike, all engines in an airplane rely on air for cooling...either through a radiator, or otherwise.

:cool:
 
Having looked at this issue for the last couple of years and run the numbers on it, I can't see putting a turbo on a 100LL engine for an RV. I would, however, install a turbo'ed diesel in a second, with water cooling. That eliminates the heat problem, and higher HP at altitude will go a long way to overcoming the added drag of the radiator. You still have to watch Vne at high-power cruise, but more an issue of situational awareness than anything else.

Deltahawk and Thielert are high on my list, and if I can get one by the time I'm ready to hang an engine, you can bet your house and kids I'll have one.
 
Jconard,
So what is your point, other than you seem to have a life's ambition to attack anything not Lyc powered? :mad:

I made a possible recommendation to answer a question. Do you have a better solution, speciffically how to get continuous 200+ hp output out of a 340 lb "air cooled" (i.e., Lycoming) engine, without burning up the heads in the process? confused:

I really have nothing personal against Lycomming products, other than their outrageous price. They are what they are- just a good engine among other possibilities, with inherent reletive strengths and weaknesses. :)
 
Mike,

Your post was completely off topic...and again wishful at best, or factually inacurate at worst.

The thread was about turbo charging a traditional aircraft engine.

And I thought it was curious that at the same time you both criticised the turbo system as too complex, and "recomended" an approach requiring an entire additional, flight critical system (psru), as well as the normal complexity.
 
Fair enough, point taken. I still think power beyond ~160 arena is approaching a point of rapidly diminishing returns as far as speed is concerned in a 9A, but possibly worth considering if improved climb rates or reduced takeoff distances are desired. That was my main observation. How best to obtain that power level, if desired, might be another issue, as you indicated.

I dont know anything I mentioned that was not factual. As far as targeting percieved failure points, Ive never heard of a planetary PRSU giving anyone trouble in a rotary engine- The old Ross amd Tracy's designs have proven as durable or stronger than the rest of the rotary design. I cannot say that for Lyc exhaust valves or crankshafts.
 
I cannot say that for Lyc exhaust valves or crankshafts


Milke, there you go again. When there are as many psru's with as many hours as there are lycoming exhaust valves and cranks, then make the comparison.

How is the PPL coming?
 
Is your point that any Lyc (of unknown age or condition) has to be a far better powerplant, ignoring every one of the part failures on record, because a lighter/more powerful competing engine with far fewer, stronger internal moving parts includes an overdesigned psru that has never failed, could? I dont get your logic.

There are far more hours logged with Rotary engines than any Lycomming product. Planetary gearsets are preferred because of their inherent strength, particularly the psru's that use a 6-gear carrier (lots of tooth contact).

IMHO, There are lots of things more problematic than a planetary gearset designed for multiples of the torque life a rotary engined aircraft will ever see- a c/s prop for example. With a rotary app, my biggest concern involves a ruptured cooling hose or perhaps a concurrent failure of both independent ignition systemsm, but not the psru.
 
There are far more hours logged with Rotary engines than any Lycomming product.

Is this a typo?

There are things more problematic than a PSRU, but not sure which on a traditional design are....I am actually unaware of a valve failure. I understand that because of the tight record, POTENTIAL problems with various crank suppliers have been identified, but again it is a statistically insignificant amount among the fleet (RV sized engines 360--320--390--etc.)

As to planetary gears...can you run a Hartzell with it? Can you run any hydraulic CS prop with them? It is not just gear teeth and raw strength, it is a dynamic environment.

When you use the moniker "imho", I am inclined to agree that it is an acurrate description of what you say.

Again, how is the PPL coming?
 
Last edited:
This is not really the best time or place to discuss these points, but to answer specific questions:

Typo? No- Mazda actually tests its products extensively under controlled conditions before they send them to market (unlike Lycomming, who sends motors to market, to beta-test out design or material flaws, before recall and make YOU pay for their mistakes :( ). Mazda conducted an interesting race engine program- parts were developed using dynometers AND then successfully tested in race conditions. And then there are the continual improvements learned from 1000's of vehicle on-the-road experiences over the last 20 years or so. As to applicability to aircraft use, the racing experiences are probably the most completely developed database, though I suppose one could easily argue that, with a rotary, stop-and-go road use is harder on an engine than continued "normal" speed (<6000 rpm) operation might be, unlike a conventional piston engine.

Metal props, including the impressive newer Hartzell designs, are not recommended with rotaries in general- it is feared that heavy metal blades can extentuate torsional harmonics, as it can with Lycs. I don't know if any have been tested extensively enough to know either way. The lighter props (wood or composite) are recommended.

Yes, you can design hydraulic prop control into a planetary gear PSRU, some do (Powersport) and most do not (including Tracy's). Most of the rotary guys using Tracy's Psru use either a fixed or an electrically adjustable pitch or C/S composite prop. I suppose that a drilled crankshaft oil passage is all that would be needed to power the prop pitch control, along with some mechanical drive arrangement to work with a C/S prop speed governer. Im personally undecided yet between a fixed composite 3-blade Catto prop or the 24-26 " IVO 3-blade in-flight adjustable Magnum composite prop (~27 lbs), with Tracy's 2.8 ratio psru.
 
Last edited:
Hey Mike,

If you get to count all of the Mazda race car hours, I thinks it's only fair to let the recip guys count all the hours of Porsche (air cooled, horizontally opposed) race cars over the last fifty years or so. :rolleyes: (And yes, I know that the newer ones utilize liquid cooling systems)
 
Hey, I didn't know Porsche made Lycomming motors, or was it the other way around :) (dont forget all the VW bugs either). Porsche likely upgraded their engines through the years, just like Mazda did, and I imagine they also did a little testing along the way too. I know for a fact that their racing parts are almost as expensive as Lyc parts... :D Actually, I think you could make a better case with old tractors- the technology is sorta similiar w/ air-cooled big bores + long stroke design+ heavy flywheel. Simple, designed for low rpm, and powerful.

The differences with the Mazda race car and current 13B based motors are minor- they just stacked a few more case section modules and 2 more rotors inside. The unique parts were the special lengthened excentric "crankshaft" and manifolds/ bigger fuel system. The good news is that all the tuning and data derived from that program still directly apply- it is interesting they reported a lot of that data "per rotor", knowing the power output was pretty much additive.

Rumor is that Mazda is coming out with a larger displacement rotary engine soon, around 1600 cc's I believe, designed to add a bit more low end torque for the RX8; it should be good for around 300 ponies and only add a few pounds more. :rolleyes: I imagine they just might be the perfect marriage for RV10's and Rockets, light and powerful without needing a turbocharger. :eek:
 
Last edited:
Typo? No- Mazda actually tests its products extensively under controlled conditions before they send them to market (unlike Lycomming, who sends motors to market, to beta-test out design or material flaws, before recall and make YOU pay for their mistakes ).

Actually not correct, Aircraft engines are extensively tested before becoming certified, and then they are again tested extensively in any given aircraft before the pair are certified, and then they are tested extensively with a particular prop before they are certified.

You are correct that the current crop of PSRUs are not capable of runing a traditional CS prop, and incorrect that the same propr creates issues for the lyc...again extensive testing.

As to the racing program....wel if you believe there are stock parts in the high end (IMSA) engines..well keep smoking whatever. The only racing application I am aware of, which uses stock parts, is the formula mazda series, in which everyone has to run a sealed engine.

As to porsche/VW they are dramatically different. I am now more convinced than ever that you have little familiarity with the rotary racing applications, racing applications, most automotive air cooled technology, and the process by which aircraft become certified.

Ever held a racing license?
Ever been involved with ANY racing series?
How is that PPL coming?
 
Jconard said:
You are correct that the current crop of PSRUs are not capable of runing a traditional CS prop, and incorrect that the same propr creates issues for the lyc...again extensive testing.
Click to expand...

Actually, several PSRUs have hydraulic prop capability (Marcotte, PowerSport, EPI, Robinson) but certainly many don't (Egg, RWS). This is not seen as a big thing in the market since MT, Quinti, Sensenich, Whirlwiind and others have or are developing good electric props. Additionally, aluminum props are seen as a weight and possible fatigue liability when combined with auto engines and their much wider rpm envelope.

I think many people forget all the electric props which were used in the '40s and and '50s on MANY different types of aircraft (P40, P38, P47, B26, B29, F4U, P39 etc.). These worked at least as well as the hydraulic ones and had other advantages in cold weather, plus no oil leaks. These numbered in the hundreds of thousands.
 
Last edited:
I have actually flown in a certified plane with an electric prop...K35 bonanza.

Sure they work great for that application, and the current crop work great for straight an level duty. But they do not react quickly enough to serve well in acro duty. As I understand Egg's website, the MT gets set to maximum rpm and then powered down before sport acro can be performed.

Probably fine for a 9...kinda a sacrifice on the 7 and 8.
 
Back to somewhere near the original topic of thread

While a one-off turbocharger installation is not for the faint-hearted, and lots of fabrication skills would certainly be nice, it can be done. (Not saying it should - just that it can). If you want to read up on the technical aspects of turbochargers and how to match a particular unit to a given engine, pick up a copy of "Turbochargers". This is targeted to auto use, but the underlying fundamentals are there. Just go to amazon.com, and search books for "Turbochargers". Happy reading!
 
William Slaughter said:
While a one-off turbocharger installation is not for the faint-hearted, and lots of fabrication skills would certainly be nice, it can be done. (Not saying it should - just that it can). If you want to read up on the technical aspects of turbochargers and how to match a particular unit to a given engine, pick up a copy of "Turbochargers". This is targeted to auto use, but the underlying fundamentals are there. Just go to amazon.com, and search books for "Turbochargers". Happy reading!
Click to expand...

The Hugh MacInnes book is still one of the best on the subject although a little dated now. The Mark Warner book "Street Turbocharging" (available at Amazon too) has a little less deep theory but more practical advice for the system design and layout. I guarantee you that you need fab skills and previous experience to install a successful, reliable and efficient turbo setup on an RV. Red hot parts coming adrift under the cowling will spoil your whole day! Even the OEs like Cessna did not get it right the first time with several ADs issued on their turbo models with regards to piping failures, melting spars etc. Some OE applications were just not designed well. Be careful.
 
Last edited:
Its a wounderful mess

I think the original topic was should I turbo? not how. However if you want to change the subject how to turbo charge, its a fascinating topic. There are all kinds of cool turbos and inter coolers to be had in the auto arena, which can be used on planes.

Superior had a Turbo IO360 kit they where developing. A normalizing deal with no inter-cooler. They dropped it. It was too expensive, about $40,000. So that gives you and idea what the turbo, wast-gate, controller and plumbing cost.

I agree with rv6ejguy, there's a lot of ways to do it poorly. Having ridged pipes and high temp silicone flex couples, like cars use, will solve a lot of the cracking going on with older OEM airplane turbo set ups. Still we are talking about routing exhaust and cracks happen.
 
Last edited:
Turbo technology has changed a lot in the last 30 years from when many OE aircraft installations were designed. The turbos are better, the wastegates and intercoolers are better and the choices vast.

I don't think any sane person on any reasonable budget would use old certified aircraft hardware to design a new turbo system. The wastegates and controllers are heavy, clunky and expensive and unnecessarily complicated with hydraulics. The intercoolers were relatively inefficient and the choice of quality turbos limited and expensive.

All the leading racers at Reno in the Sport Class use modern automotive type hardware which in function and quality is now on par or better than the certified stuff. Standard auto wastegates are now available with 347, 253MA stainless or even Inconel 625 bodies, silicone/ Nomex diaphrams and high temp 17-7 SS springs. These are capable of operating at over 2000F continously. The standard Garrett turbos now have Inconel wheels, modern compressor designs up to 85% efficient, better bearing materials including ceramic ball bearing options and superior Ni-resist type turbine housings. The modern air to air intercoolers offered by BEGI and similar have been designed on computer for superior heat rejection and much lower pressure drop than the old AiResearch cores. Although most certified turbos had nitrided shafts, shaft wear is not an issue on Garretts in my experience at least using Mobil 1 oil. Maybe when running inferior (for the turbomachinery) non-synthetic aircraft type oils though.

The hardware is almost never an issue today but the exhaust system still is. Many OEs never had proper support structure for the heavy turbos and used tubing which was too thin for lasting performance. Lots of cracking pipes were the result. They should have known better.

If you are doing your own, a few tips:

Use Ti stabilized 321 or Inconel for the entire system. 304 is not suitable for these temperatures and stresses. Use .058+ wall tubing. .035 will fall apart in a fraction of the time.

Any long runs or ones at obtuse angles must be slip jointed or use bellows.

The turbo weight must be supported by a substantial structure. You can't hang it off the headers unless they are very thick (.090+).

External wastegates must also have slip joint or bellows connections due to differential expansion chnages when flowing/ not flowing exhaust.

If the turbo oil discharge is at nearly the same level as the oil in the sump, you will need a scavenge pump. The climb attitude in aircraft often make pumps mandatory.

All aircraft installations should be intercooled, even normalized ones. To do otherwise is a recipe for inefficiency and/ or engine disaster, especially on air cooled engines.

You need proper fuel and spark management under all operating conditions.

Bruce Bohannon's Exxon Tiger showed what could be done with an air cooled engine and modern turbocharging ideas. Very impressive but he had professional design help and plenty of sponsorship$$$.
 
Last edited:
QUOTE=gmcjetpilot

"Superior had a Turbo IO360 kit they where developing. A normalizing deal with no inter-cooler. They dropped it. It was too expensive, about $40,000".


Hi.

They didn't drop it. They fully developed it, but it is only available presently for the Lancair Legacy. The reason is as follows: They will only sell it through kit manufacturers who are willing to develop FWF systems for it. Which makes sense, because ram-air cooling will need a whole lot of testing.
(You can confirm this in the FAQ section at XP).

My 2 cents about turbos:

For me, the engine that makes sense to 'turbo' in an RV4, 6, 7 or 8 is the 150hp 320. That way, potentially exceeding Vne becomes less likely in the teens. (As opposed to a turbo-install on the 180 hp XP-360, which is designed for planes with a Vne hovering around the 300 mph mark, who have no problem going into the 20s --read: Lancair).

The 320 could potentially be 'normalized' so that peak-performance is in the low teens, to just give us an extra boost over the mountains, nothing fancy.

So, as logic would dictate, a horsepower sacrifice at low altitude, for the promise of performance in the teens. (The same principle behind Thielert, incidentally).

I wholeheartedly believe that it is doable and that there would be a market for it.

But here's why it won't happen: Van is affraid of abuses. He wants it so that
cruise hp will never exceed Vne. This will always keep us peaking in the 8-10,000' range, with diminishing returns above that. He has the life and reputation of his business to consider, as well he should. If he doesn't OK it, XP will never develop it, or sell it to us mortals.

Anyway, that's my 2 cents.

PS: Would anybody kindly contribute figures as to what they are 'trueing' at 16,000' MSL on a normally-aspirated 360? I suspect this altitude gives us good over-the-rockies performance to meet many MEAs. Such figures will lend cred to earlier arguments that 'bigger' is better than 'turbo' if all you want is performance in the teens and not twenties.
 
RV Tony said:
Would anybody kindly contribute figures as to what they are 'trueing' at 16,000' MSL on a normally-aspirated 360? I suspect this altitude gives us good over-the-rockies performance to meet many MEAs. Such figures will lend cred to earlier arguments that 'bigger' is better than 'turbo' if all you want is performance in the teens and not twenties.
Click to expand...


I don't have all my test data on this computer, but I think I was truing in the 160's (knots) at 16,000'. And you really do have to be careful to keep the TAS under the flutter limit (200) when coming down! It helps to have TAS displayed on the EFIS....

Paul
 
This thread is a classic example of people ignoring the original question and imposing their opinions on the topic. I too am very interested in the idea of using turbocharging or turbonormalizing *maybe* one day on my engine.

As to all those who forecast doom, gloom and question the need for a turbocharching/normalizing system, thanks for the concern, but *I've got it*. Flying a homemade airplane involves balanacing risk against benefit. Use of a turbocharging system involves weighing risk versus benefit.

Thanks to rv6ejguy for the very helpful and practical info on automotive systems and how they might be useful on an aircraft engine! Sounds like my thinking one of these automotive system might not be too far off track some day.
 
Turbos

Bryan,

What YOU are saying is you don't want to hear any "cons" to the proposition of turbocharging. No matter how you slice it, there are many more reasons NOT to turbocharge an RV than there are reasons to do it. Don't ask the question if you don't want to hear the answer.
 
Low Pass said:
This thread is a classic example of people ignoring the original question and imposing their opinions on the topic. I too am very interested in the idea of using turbocharging or turbonormalizing *maybe* one day on my engine.

As to all those who forecast doom, gloom and question the need for a turbocharching/normalizing system, thanks for the concern, but *I've got it*. Flying a homemade airplane involves balanacing risk against benefit. Use of a turbocharging system involves weighing risk versus benefit.

Thanks to rv6ejguy for the very helpful and practical info on automotive systems and how they might be useful on an aircraft engine! Sounds like my thinking one of these automotive system might not be too far off track some day.
Click to expand...

If you fly in the mid teens over mountains especially, the turbo can be very handy. The Vne thing is just a matter of paying attention and observing the limits- something we should all be doing anyway and not much different from descending in an O-360 powered RV from these altitudes- power should be pulled back a bit.

I can relate a couple of scary mountain flying stories from two friends in naturally aspirated aircraft (one an RV) caught in massive descending air with full power on for over 15 minutes and still being forced down right to the deck. Turbos may have helped them out here at the high density altitudes. Fortunately the descending air stops at the ground but seeing the tree tops coming up at you with full power on and best climb airspeed will give you new respect for mountain flying.

For flat land RV fliers, turbos don't make a lot of sense for most missions unless you enjoy sucking on oxygen and like to catch the good tailwinds up high for long trips. You can get an extra 20 knots or so at 15,000 feet.

Done correctly with the latest hardware, maintenance should be minimal but you always have a bit of weight and a drag penalty at lower altitudes.
 
More turbos........

Ross,

Post a picture of your engine compartment (FWF) so people can see the realities of turbocharging. Might also be helpful to the boys if you posted links to the massive amount difficulty you had keeping that engine cool. Got to say it was a real testimony to your technical prowess........but practical?????
 
I think we are talking turbonormalizing air cooled Lycos here. I don't see cooling as a big challenge here with a proper intercooler setup and a cowl flap operated below 18,000 feet. On the Sube, my cooling is good now and I'm still doing some more with it in a couple weeks to reduce weight and complexity. Lessons to be applied to the RV10.

The hardest part is fabbing the package to get it to fit efficiently and reliably under the cowling. The operation is pretty straightforward. Just push the throttle up and the wastegate takes care of the MP automatically. You don't really know it's there. I fly just with the throttle below 9500.

Yes, there are other complexities involved as discussed in a previous post and certainly 95% of RVers probably don't need turbos but hey, if someone wants to, it can be done. This is experimental aviation after all. Power to the people with vision and desire and sorry- sour grapes to those who think small and discourage everyone who wants to do something different. Just go into something like this with both eyes open.

Bruce Bohannon, 47,000 feet in a highly modified RV4 is impressive- don't try this at home! :) :cool:
 
(Turbo)supercharging

Another engine that might benefit from a supercharger would be a 0-235. Light and fast.

Not much talk about belt driven superchargers here. It has a lot of appeal on low displacement engines where there is not much to gain in efficiency by capturing the waste heat and pressure. Move the alternator back to the vac pump pad, put the supercharger in its place up front. Solves many of the exhaust plumbing-related issues mentioned earlier.

It would be useful in the high mountain west. Most of the airports we land at are above 6000 and many above 7500. On a warm day with bumps and ever present waves, the climb rate when full of fuel does not feel, even in an RV, all that impressive (172s are often grounded around here in these situations). On top of that, most of the high airports are surrounded by terrain in close proximity that is 5 to 8k above the airport, so big climbs are a fact of life. I don't need to go any faster, just want the climb rate that sea level pilots enjoy!

There is a normalized belt drive supercharger std for 182s that looks pretty simple and it would be even simpler on a fuel injected engine.

If the "how" was easier, maybe the "should I" would be affirmative.
 
The vacuum pump drives are not designed to deliver the kind of torque or rpm required to spin a supercharger unfortunately. The centrifugal types like Vortec are better suited and safer for aircraft and could be adapted to an O-235 but they are a bit of a drag on the engine unless clutched somehow. Can and has been done on similar engines.
 
Ironflight said:
I don't have all my test data on this computer, but I think I was truing in the 160's (knots) at 16,000'. And you really do have to be careful to keep the TAS under the flutter limit (200) when coming down! It helps to have TAS displayed on the EFIS....


Thanks Paul! These figures should be plenty for most all our needs. And you get these from an O-360. Plenty 'nuff for these birds.

By the way, sweet plane you got there, with the twin GRTs and the cool paint.
Click to expand...
 
Thanks Tony - the do get along quite well....and I have to pinch myself everytime I get to fly the Valkyrie to see if its real!

Paul
 
rv6ejguy said:
...full power on for over 15 minutes and still being forced down right to the deck. Turbos may have helped them out here at the high density altitudes...


YIKES!! :eek:

Another way to potentially avoid the pegged VSI over terrain: Fly very early. :)


Back to the turbo subject:

Honestly guys, if Paul gets 160 KIAS @ 16k, and has to be very careful not to exceed Vne on descent with his O-360, then from these numbers, we can extrapolate that a blower on a Lyc is not a logical choice for the average RV pilot. (Unless you're going after Mr. Bohannon's record, in which case, tip of the hat to you, sir).

If you insist that you wanna fly in the 20's with a mask, then a TIO-360-powered Lancair Legacy FG is the ticket, with a Vne way above ours (and a price-tag to match).

Blue skies!
Click to expand...
 
Depends on how much fuel you want to burn but 180 knots at 15,000 and about 11.0 gallons/hr. The prop is not well matched however and I expect those numbers would both improve a lot with a different prop.
 
Supercharger

Ross

I meant drive the alternator at the vac pad so that you could put a belt drive supercharger in the place of the alternator up front. I agree that a centrifugal unit would be best for this app. Cruise losses could be cut by putting a second throttle plate upstream from the supercharger. This throttle could also control boost. A magnetic door bypass downstream from the supercharger and intercooler (ala. Tornado Alley) would allow normally aspirated operations when preferred.

Sticking with the original question - If supercharging could be made simple and safe from a mechanical standpoint, of course there are applications where RVs would benefit from having one. If based at sea level and most flights near it, I would not be daydreaming on the subject. Certainly not if I had to figure out how to deal with an exhaust driven turbo. If you were based in the Andes or Himalaya, I'm sure that once you had it, you would not fly without it. I guess most of us are somewhere in between.

A little more speed would be nice although I find a rarely operate for top speed anyway. Having a 2000 fpm climb instead of 600 fpm around the big hills though would be sweet!
 
True, not Indicated

RV Tony said:
rv6ejguy said:
Honestly guys, if Paul gets 160 KIAS @ 16k, and has to be very careful not to exceed Vne on descent with his O-360.......
Click to expand...

Just to be clear Tony, that is KTAS at that altitude, not KIAS. In a no-winf case, lower is much more reasonable, but if you can catch a really good tailwind, taake to the bottle (O2 that is :p ) and climb for it!

Paul
Click to expand...
 
Yukon said:
Bryan,

What YOU are saying is you don't want to hear any "cons" to the proposition of turbocharging. No matter how you slice it, there are many more reasons NOT to turbocharge an RV than there are reasons to do it. Don't ask the question if you don't want to hear the answer.
Click to expand...
Not true at all. I just don't want people telling me "you don't need a turbocharger!" Sometimes the point of doing things with an experimental plane are for the satisfaction of accomplishing a challenge.

If you and others want to slap on a firewall fwd, certified engine package with all STC's and PMA parts - do it. But don't try and quash the discussion and say don't consider turbocharging. Like I said before, there are plenty of aviators who think you flying an experimental is excessively risky.

Last, I didn't ask the questions. But I did want to hear the answers.
 
Last edited:
zav6a said:
Ross

I meant drive the alternator at the vac pad so that you could put a belt drive supercharger in the place of the alternator up front. I agree that a centrifugal unit would be best for this app. Cruise losses could be cut by putting a second throttle plate upstream from the supercharger. This throttle could also control boost. A magnetic door bypass downstream from the supercharger and intercooler (ala. Tornado Alley) would allow normally aspirated operations when preferred.

Having a 2000 fpm climb instead of 600 fpm around the big hills though would be sweet!
Click to expand...

Cool ideas. Clearly you've put some thought into this. I say go for it and post some pix and results if you do.
:)
 
Low Pass said:
Not true at all. I just don't want people telling me "you don't need a turbocharger!" Sometimes the point of doing things with an experimental plane are for the satisfaction of accomplishing a challenge.

If you and others want to slap on a firewall fwd, certified engine package with all STC's and PMA parts - do it. But don't try and quash the discussion and say don't consider turbocharging.
Click to expand...

Absolutely. For me it is the challenge of doing something different. For others, the quickest, easiest way to get their RV airborne is the way for them (Lycoming). Others want to tweak for speed, others want to save some fuel, slow down and enjoy the RV experience and flying in general. Whatever turns your crank. The diversity of the RV world is what makes it interesting. I like to read about new ideas and accomplishments. Engine and airframe mods are of particular interest to me.
 
Ironflight said:
Just to be clear Tony, that is KTAS at that altitude, not KIAS. In a no-winf case, lower is much more reasonable, but if you can catch a really good tailwind, taake to the bottle (O2 that is :p ) and climb for it!

My bad! My brain meant KTAS, but my fingers don't always listen.
Regardless, your numbers are encouraging.

Have a good weekend!
Click to expand...
 
You must log in or register to reply here.