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Has anyone here put a turbo on a -10?

smash603

Member
Im not trying to be controversial here but.... has anyone tried to Turbo normalize or supercharge a 540 on a -10? I have searched the forums on the topic but never actually found anyone that has done it... If someone has, they probably haven't said anything in fear that they will be berated by someone referencing "Flying high and fast" Safety is paramount- I am trying to see if it is possible to get a little better high altitude performance... not fly faster then Vne. Thanks!
 
I seem to remember some pictures of a -10 with twin turbos.

The issue with the RV's is that our Vne is based on True Airspeed, not Indicated. With turbo's and the ability to make full rated power at altitude, there is a very good chance you can run right past Vne.

That said, I can see many reasons why someone would want a turbo, other than expense, complexity, and weight.

Good luck and if you do it, please post pictures and comments.
 
I had twin turbos on my EG-33 Subaru powered RV-10 but sold before it flew. Engine not sold with airframe.

Keep the speeds down to 190 KTAS and you have enough buffer. I've been flying a turboed -6A for 16 years. No worries keeping speeds below 182 KTAS Vne. Pull the power back on descent. People who don't fly turbo stuff think this is so hard to do. Nope. Just fly it by the numbers and use your brain (which I hope folks are doing already). Easy rule in cruise coming down for descent- nose down, throttle back.

Considerations:

Weight, packaging, fuel and ignition control, wastegates, turbo matching, intercooling, oil cooling, exhaust system construction and turbo mounting, oil scavenging for turbos.

If the turbos are mounted low, you'll need an oil scavenge pump. These are available for certain models of factory turbocharged Lycomings. I used to know the PNs but it's been a while. Should be easy enough to look something up for a Navajo or similar.

You'll probably add 35-50 pounds of hardware up front to do this. Could offset some of this effect with a composite prop.

Will need a 321 SS, heavy wall exhaust system with slip joints. Turbos need to be supported by proper brackets, not hung off the exhaust.

Probably will need a larger oil cooler, the turbos dump more heat into the oil.

Intercoolers a good idea even normalizing if you're flying above 12,500 regularly.

I can help you match turbos and offer sources for wastegates, boost control, intercooler cores etc. if you decide to go ahead.

This will be a pretty big job, lots of custom fab work.
 
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I think you are joking but.... again, like I said in my original post I have read the article. I am looking for high altitude performance not to exceed Vne...

No, I completely missed the part where you said you read it. Chalk it up to reading on mobile before the coffee kicked in! :D
 
Much as I like turbos, you have to consider the cost and effort involved to go 15-20 knots faster in a -10. Could be worth it for some.

In an airframe with higher Vne like a Lancair, the effort may be more worth it getting 30-40 knots more TAS up high.
 
I can't see any detail on how the turbo is supported but if it's just hung off .035 wall tubing, that's not a good plan for longevity.
 
Disclaimer- Do not read this as me being pompous- I personally would like to see Vans present some technical data that shows evidence of flutter above 200KTAS... the same Vne is given for multiple types of Vans aircraft, I am not an aeronautical engineer but from what I understand flutter is airframe dependent.... I have read or seen numerous accounts of individuals exceeding 200kts TAS out of ignorance (because it is not widely known) or by accident. I have only been able to find one or two instances of accidents that could possibly be contributed to flutter that were believed to be well in excess of Vne... I understand that limits are there to keep us safe and I have no intention of exceeding them but the nerd in me would like to see the data...
 
Disclaimer- Do not read this as me being pompous- I personally would like to see Vans present some technical data that shows evidence of flutter above 200KTAS...

Vans job is to keep you safe to the best of their ability. That involves building in a safety margin for plane to plane variation on flutter margin, g-loading, etc. The last thing they are gonna do is share their data. Someone would use it improperly and hurt themselves. Alternately, it could be used against them in court.
 
Vans job is to keep you safe to the best of their ability. That involves building in a safety margin for plane to plane variation on flutter margin, g-loading, etc. The last thing they are gonna do is share their data. Someone would use it improperly and hurt themselves. Alternately, it could be used against them in court.


Alrighty then. Never mind I guess I will take their word for it...
 
I always wonder why some people want to flout the manufacturers Vne recommendations. Yup we have folks who've exceeded Vne and lived to tell about it. Do that at your own risk though. If you do get flutter, it can all be over in seconds. That wouldn't a good end to your day as you plummet earthwards surrounded by aluminum confetti as one fellow put it.

There appears to be a good margin of safety built in which is why we haven't seen many accidents attributed to flutter. Maybe a good idea to leave it that way.

Not every RV is built exactly the same as Van's test aircraft which is why they have a wide buffer I suspect.

There are other airframe choices if you need to regularly go 220+ knots. Just my 2 cents.
 
I too have been thinking about this. Reading the aforementioned article, the main concern from Van's seems to be the possibility of exceeding VNE, which should be calibrated in TAS as opposed IAS. Point well taken and understood.

I am by no means an expert, but it seems that with modern avionics such as the G3X, from what I've read it should be possible to calibrate the VNE arc on the airspeed tape in terms of TAS as opposed to IAS. So, theoretically regardless of flight conditions, as long as you don't venture into the red arc (calibrated in TAS), you should still be able to enjoy the improved climb performance, higher service ceiling etc. of a turbo while still remaining safe below VNE?
 
I am by no means an expert, but it seems that with modern avionics such as the G3X, from what I've read it should be possible to calibrate the VNE arc on the airspeed tape in terms of TAS as opposed to IAS. So, theoretically regardless of flight conditions, as long as you don't venture into the red arc (calibrated in TAS), you should still be able to enjoy the improved climb performance, higher service ceiling etc. of a turbo while still remaining safe below VNE?

I think with the prevalence of modern glass cockpits and the capabilities that they bring to easily display TAS it seems like it would be fairly easy to identify and remain below Vne without a problem...

From what I understand Van?s has built in a margin of safety with a Vne of 200kits TAS, should we build in another margin of safety and only fly at 170kts TAS?
 
A good RV-10 will already true 170 KTAS. There is little point in the turbo if that's your target.

That?s what I am saying, Guys run 170kts consistently.... is there a problem with targeting 195kts? Or is the margins that Vans built in not enough margin?
 
That?s what I am saying, Guys run 170kts consistently.... is there a problem with targeting 195kts? Or is the margins that Vans built in not enough margin?

Engineering margins belong to the engineers. Exceed them, and you're a test pilot.
 
That's a fact

"...Engineering margins belong to the engineers. Exceed them, and you're a test pilot..."

That's a fact.

"...If you do get flutter, it can all be over in seconds..."

That's a fact...and it doesn't matter how good a pilot you think you are.
 
"...Engineering margins belong to the engineers. Exceed them, and you're a test pilot..."

That's a fact.

"...If you do get flutter, it can all be over in seconds..."

That's a fact...and it doesn't matter how good a pilot you think you are.



So targeting 195kts True in cruise is completely acceptable?
 
Agree

As Ross said, I would think that acceptable in smooth air...

Now consider the increase in fuel flow to get that extra 15-20 knots...it?s always a compromise because of the TANSTAAFL principle...
 
If you're going high, the fuel flow increase will be minimal, should still be able to run LOP at close to 24 squared. The decreased drag up there doesn't need high power. In fact, you could drop the rpm some more as Dave Anders does, maybe run 2200 and 25-26 inches and get even better economy by cutting engine frictional losses and increased piston blowdown forces from the turbo compressor.
 
Interesting Data

"...If you're going high, the fuel flow increase will be minimal, should still be able to run LOP at close to 24 squared. The decreased drag up there doesn't need high power. In fact, you could drop the rpm some more as Dave Anders does, maybe run 2200 and 25-26 inches and get even better economy by cutting engine frictional losses and increased piston blowdown forces from the turbo compressor..."

I would be interested in some real world data. Again, the TANSTAAFL principle applies. It is definitely better to go higher but there are ALWAYS costs involved. There is definitely a break even point and it would be interesting to find it for the -10. Given the maximum defined difference in TAS between a NA -10 and a turbo -10, it should be possible to determine the optimum solution...from there it would be easier to decide if the added complexity would be worth it to each individual.

As has been stated previously, if you want to fly at much higher speeds, there are other aircraft out there there will do it without pushing the engineering limits of the airframe...

...but it would still be nice to know for the -10...:D
 
The extra time to climb uses more fuel and you save some of that on the way back down. The ROC on a -10 with a turbo makes that extra time minimal.

Cruise climb LOP once below 75% and you save more fuel.

Really going right to 17-25K to if the winds are favorable will give you the best MPG. You may have to watch the TAS above 17K though and you may have to bring the rpm back to cut the hp down-but that saves more fuel still.

Turbos are magic...
 
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The extra time to climb uses more fuel and you save some of that on the way back down. The ROC on a -10 with a turbo makes that extra time minimal.

Cruise climb LOP once below 75% and you save more fuel.

Really going right to 17-25K to if the winds are favorable will give you the best MPG. You may really have to watch the TAS above 17K though and you may have to bring the rpm back to cut the hp down-but that saves more fuel still.

Turbos are magic...

And this gets to the heart of the OP. If you tend to operate at high altitudes, or need to climb from SL to 16,000 (say, if you live around the Sierra's), a turbo will definitely help - especially on high DA days, like we've experienced all summer here in N. Ca.

I personally think a turbo is a great option and should not be dismissed simply out of fear that the pilot will not manage their power properly. Stay within the operating limitations of the airframe and you'll be fine. And further comments about being in calm, or non-turbulent, air at 195KT is also true for that condition anytime you're above the top of the green band, going faster then Vno, which is 152KIAS for the RV10. At 16,000', 152 KIAS is about 190 to 195 KTAS (depending on OAT), so unless we've now changed the yellow band to true airspeed as well, there should not be a problem.

There are many things pilots need to do to ensure a safe flight; managing power and speed are just two of them.

Very doable, economical and it gets you farther away from the cumulus granite when used properly. I like it.
 
So now let's discuss the pros and cons of a brushless electric supercharger versus a typical turbocharger...:D

At FL180, the pressure ratio to develop 25 inches MAP is around 1.7. In cruise, the compressor would have to flow around 33 pounds/ min. Me thinks that would require at least 5,000-10,000 watts. Divide that by 14V and you get 357-714 amps.

Hard to beat the energy present in the exhaust stream...
 
At FL180, the pressure ratio to develop 25 inches MAP is around 1.7. In cruise, the compressor would have to flow around 33 pounds/ min. Me thinks that would require at least 5,000-10,000 watts. Divide that by 14V and you get 357-714 amps.

Hard to beat the energy present in the exhaust stream...

You have the s/c motor running at, what, 90% thermal efficiency. I don't know what efficiency the compressor wheel would run at. Wires running at (WAG) 98%. And the alternator running at 55% efficiency. That 10kW now takes about 21kW of power to run. That's 28hp. And I'm sure there are more inefficiencies that I've forgotten.
 
Another challenge that (I don't think)has not been mentioned is engine cooling.

The biggest benefit of a turbo (If you truly discount the speed benefits up high) is to help performance on high density altitude days. High density altitude days by definition are HOT days.

If The turbo provides more power at high altitude than you could produce if normally aspirated, then you will have to have the ability to cool that additional power. The air begins to get mighty thin even in the upper teens.

The few people that have successfully integrate a turbo on an RV have found this to be the biggest challenge. It requires a huge amount of cowling and cooling system modification.
 
You have the s/c motor running at, what, 90% thermal efficiency. I don't know what efficiency the compressor wheel would run at. Wires running at (WAG) 98%. And the alternator running at 55% efficiency. That 10kW now takes about 21kW of power to run. That's 28hp. And I'm sure there are more inefficiencies that I've forgotten.

My guess was pretty wide and just to really show that electric supercharging at this mass flow and pressure ratio isn't viable with a 14V system. Audi uses 48V for their electric supercharger and it's only for short duration and at partial mass flow to get rid of turbo lag at low rpm. I think that's still around 7000 watts.

Yes, when you figure in motor, controller and compressor efficiencies. It current would be much higher.
 
Another challenge that (I don't think)has not been mentioned is engine cooling.

The biggest benefit of a turbo (If you truly discount the speed benefits up high) is to help performance on high density altitude days. High density altitude days by definition are HOT days.

If The turbo provides more power at high altitude than you could produce if normally aspirated, then you will have to have the ability to cool that additional power. The air begins to get mighty thin even in the upper teens.

The few people that have successfully integrate a turbo on an RV have found this to be the biggest challenge. It requires a huge amount of cowling and cooling system modification.

Given the low Vne, you wouldn't want to maintain SL power to 18 or 24K as you'd bust that speed as soon as you lowered to nose at 30 inches MAP. I'd say you'd be running closer to 22-25 inches and 2200-2300 rpm.

If you can cool 260hp at SL at 170 kts. and say 25C, you can cool 182hp (70% power) at 190 KTAS and 18,000 feet at 0C. You need intercooling to keep the induction temps down and as I said before, you'll need a bigger oil cooler for sure. The extra airflow for these will add some drag of course.

Very doable but is 20 knots worth the trouble and expense?
 
and...

...and now we get to the heart of the matter...

"...Very doable but is 20 knots worth the trouble and expense?..."

That is definitely the question...

Of course what would really be cool is a couple of small jets bolted to the wings of the -10!
 
...and now we get to the heart of the matter...

"...Very doable but is 20 knots worth the trouble and expense?..."

That is definitely the question...

Not necessarily. In my mind at least (and presumably that of the OP), it's less about the 20 knots and more about the potential increase in climb performance and service ceiling (for example getting on top of weather, increased safety margin over mountainous terrain, crossing large bodies of water, etc).

Whether it's "worth" it or not would depend on what those gains actually are, and the cost (in terms of both time and $) to overcome some of the practical design challenges that have been mentioned such as cowling mods, cooling considerations, etc..

Does anybody know the builders/owners of that plane in the youtube videos and if they would be willing to chime in here with their building experience and real-world performance data?
 
That?s what I am saying, Guys run 170kts consistently.... is there a problem with targeting 195kts? Or is the margins that Vans built in not enough margin?

I think trying to target 195 TAS is a foolish plan. That is only 2.5% from VNE. I have over 18,000 hours total and have had several instances where I?ve exceeded VNE (not in a Vans RV) due to circumstances beyond my control. Winds, mountain wave, or an aircraft malfunction are just some of the ways that can cause you to exceed VNE.

If you want to go faster I would encourage you to consider another airframe. Just my $.02.
 
Given the low Vne, you wouldn't want to maintain SL power to 18 or 24K as you'd bust that speed as soon as you lowered to nose at 30 inches MAP. I'd say you'd be running closer to 22-25 inches and 2200-2300 rpm.

If you can cool 260hp at SL at 170 kts. and say 25C, you can cool 182hp (70% power) at 190 KTAS and 18,000 feet at 0C. You need intercooling to keep the induction temps down and as I said before, you'll need a bigger oil cooler for sure. The extra airflow for these will add some drag of course.

Very doable but is 20 knots worth the trouble and expense?

I defer to your experience Ross, so maybe you are right. I was just quoting from the experience that a couple of RV modifiers have had.
They could easily cool down low but as soon as the got in the upper teens / lower 20's and tried to operate at normal max continuous power, they couldn't keep the temps under control until they did some rather radical (and ugly in my opinion) adjustments to the cowl cooling air inlet and outlet sizes.
 
Another challenge that (I don't think)has not been mentioned is engine cooling.

The biggest benefit of a turbo (If you truly discount the speed benefits up high) is to help performance on high density altitude days. High density altitude days by definition are HOT days.

If The turbo provides more power at high altitude than you could produce if normally aspirated, then you will have to have the ability to cool that additional power. The air begins to get mighty thin even in the upper teens.

The few people that have successfully integrate a turbo on an RV have found this to be the biggest challenge. It requires a huge amount of cowling and cooling system modification.

That's only true for developing more power than 260hp with a turbo. Maybe the OP only wants to maintain 260 in the climb well into the teens. I personally am targeting 18,000 as a max operating altitude, simply because I hate wearing a mask...but others may desire higher.

If the cowl can handle 260 hp NA, it can handle 260 hp turbo'd - as in turbo-normalizing. Going beyond 260, yes, then you need modified air flow.

However, let's say you want to use a 2.0L engine that normally produces 200 hp, but with a turbo to develops 260 hp. Let's say you would cruise at about a 200 hp setting, the airflow of the Van's cowl would be fine in this installation. It's a turbocharged installation, but the heat developed would be no more than the total sum developed by 260 hp.
 
That's only true for developing more power than 260hp with a turbo. Maybe the OP only wants to maintain 260 in the climb well into the teens. I personally am targeting 18,000 as a max operating altitude, simply because I hate wearing a mask...but others may desire higher.

If the cowl can handle 260 hp NA, it can handle 260 hp turbo'd - as in turbo-normalizing. Going beyond 260, yes, then you need modified air flow.

However, let's say you want to use a 2.0L engine that normally produces 200 hp, but with a turbo to develops 260 hp. Let's say you would cruise at about a 200 hp setting, the airflow of the Van's cowl would be fine in this installation. It's a turbocharged installation, but the heat developed would be no more than the total sum developed by 260 hp.

In theory that may be correct but in practice by those that have actually done it, it hasn't worked that way.

Cooling the engine at 8000 ft while producing 75% power and cooling it at 18000 while still producing 75% power are two totally different situations.
 
Scott is correct. Cooling becomes more challenging as air density falls with altitude. Remember cooling is about mass flow. Cooling in the climb, where power is high and mass flow is low is most challenging.

Wanting to run more than 30 inches up high may need some mods on a -10.

In an atmo engine, power conveniently drops off as altitude increases which lowers the heat load. This doesn't happen on a normalized engine or boosted one. Might be ok on cool or cold days but not on over standard ones once you get above 10,000 or so.

It comes down a lot on how much power you want to push, what altitude and the OAT.

I don't think it's realistic to think you'll be able to run 35 inches at 18,000 feet without cooling mods and you couldn't use that much MAP in a -10 anyway up there as you'd be way over Vne.

As far as increased climb capability, yes that's a benefit but you may find you have to keep the nose lowered to keep the CHTs down so the ROC may be little better with the turbo as with an atmo engine.
 
Think liquid cooling to solve CHT issues.

Regardless of your altitude, the heat load from a fixed horsepower is the same; yes, thinner air requires more flow to obtain the same mass flow rate. And yes, you need additional air flow for an intercooler. But these are not reasons to not use a turbo, they're just implementations you need to engineer to use one.

I'm solidly in the camp that turbos are a good thing to improve engine efficiency and maintain power through the climb and into cruise.

There are many good turbo-charged aircraft out there, turbo-normalized too, both certified and experimental. It's just a matter of what your goals are and the effort you're willing to apply to achieve them.

Very doable on a -10.
 
Yes very doable if you address all these areas.

Liquid cooling solves many of these issues but that's not applicable to a Lyc 540. Not sure if the Cool Jugs are still being made?

At Reno they're pushing insane hp numbers but lots of ADI and spray bar water, lower altitudes and much higher speeds (mass flow) to compensate. CHTs are also running higher than what you'd want on your cross country plane.

I'm all for seeing some more people try a turbo installation on a -10. :)
 
Yes very doable if you address all these areas.

Liquid cooling solves many of these issues but that's not applicable to a Lyc 540. Not sure if the Cool Jugs are still being made?

At Reno they're pushing insane hp numbers but lots of ADI and spray bar water, lower altitudes and much higher speeds (mass flow) to compensate. CHTs are also running higher than what you'd want on your cross country plane.

I'm all for seeing some more people try a turbo installation on a -10. :)

Cool Jugs are still around.
http://www.liquidcooledairpower.com/cj-overview.shtml

What's interesting to me is the thirst for even more speed when we have pretty fast ships now. I was flying a Citabria for several years before my RV8. The first year I was flying my RV, I thought I was flying supersonic. Now I find myself occasional complaining about 165KTAS with my FP prop to some of my friends and they roll their eyes. We have great planes that fly plenty fast as designed - and that keeps them reasonably safe. Let's keep it that way.
 
Website is there but last updated in 2003...

Anyone flying them and are they still producing and selling them?
 
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