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Seeking 200mph+ with a 9A, suggestions?

R

Rick of Austin

Well Known Member
Edit : oops I meant 200mph+ not adding 20mph but that would be nice too :)
My 160hp -9a runs right around 195 to 198 mph wide open of course at 2500 as shown on the GPS. This is with a sensenich thats soon to be replaced with a Catto 2 blade, it also has 2 mags.
Put as simply as possible how to go faster?
Should I expect an improvement with the Catto? At least then I can wind it out more, how about a Lightspeed EI?
My thoughts are:
Flap hinge fairings similar to the late model Mooneys
Empenage hinge access hole closeouts, again unbashfully copying the mooneys
Possible a boattailed fairing aft of the cowl exit?
Streamline the pitot tube.

Please lets avoid any talk of why, VNE, manuvering speed etc.
Thanks Greatly
Rick
 
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Spin it faster. 2700 RPM is your redline, spin it up there as the engines are designed to run at the redline to TBO.

I've looked at making those flap hanger mods and have a plug for the Vetterman boat tail, just waiting for me to fiberglass it up.
 
Rick,

What Bill said. I can get just at 200 mph on my 9 with the Sensenich 85" prop running WOT (~2750) at 8500 ft elev. I've thought of pitching it another inch or two and could maybe get a couple more mph, but it would certainly lengthen my ground run on takeoff. And I'm using a slightly bigger engine.

greg
 
Thanks & Prop for sale

Thanks bill and Greg for the input. Yep, first thing is to get rid of the tuning fork on the front of the engine so it can be turned up! I love spinning them fast. The probably a EI since those are two no brainers.
Within a week I should have my Catto on there and I'll post the changes although I dont spend a lot of time getting super accurate data.

Which means I have a prop for sale.
Sensenich from Vans for a 160hp RV-9a with 230hrs including a very nicely matched dead centered spinner, bolts etc right off the plane.
Without doing much research maybe in the $2,400 range?
 
drag reduction!

The biggest bang for your buck is drag reduction!
Wax the entire airplane. Fairings and cooling related drag is huge.
EI will really help. I think Klaus S. has wheel pant Fairings that fit RV tires, they are a low drag air foil.
 
Hi reading this topic got me to think I have something wrong...

I am currently flying my RV9A Lycomming 160hp Hartzell on engine break-in (has only 38 hours yet) at 2400rpm , 24map and the most I can get out of this arround 8500ft is 163mph TAS. Is that normal/average for this rpm and map setting?

I am asking that because I haven't yet tried 2500rpm (max map , full throttle) to get the 192-200mph folks here are describing.... how much power (in percent %) would this setting 2500rpm full throttle yield...? Is that safe for engine break-in period?

Another thing N941WR said that is safe to fly at 2700rpm is that true even at engine break-in period???

people that are reaching 192-200mph TAS what is you fuel consumption at that power setting? You fly that at 50F ROP or 100F ROP?

Much thanks for the responses because by now, I CAN'T GO ANY FASTER THAN 163 mph AND THIS POST LET ME THINKING maybe is just my lack of experience/knowledge yet... have to try other rpm and map settings....
 
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To wax, or not to wax ... that is the question ...

rv9av8tr said:
The biggest bang for your buck is drag reduction!
Wax the entire airplane ...
Click to expand...

I would swear that many years ago I read an article in "Flying" or "Pilot" where waxing for speed was dispelled as a myth, since the air that we fly through doesn't actually touch the plane due to the boundary layer of air molecules.

I've searched high and low for that article and can't find it. Maybe some of the more aeronautically knowledgeable on VAF can address the validity of waxing for more speed.

If nothing else, it makes the plane look prettier. :)
 
ALMARTON said:
Hi reading this topic got me to think I have something wrong...


Much thanks for the responses because by now, I CAN'T GO ANY FASTER THAN 163 mph AND THIS POST LET ME THINKING maybe is just my lack of experience/knowledge yet... have to try other rpm and map settings....
Click to expand...

Have you got the wheel pants and leg fairings on yet???

Added just under 20 MPH on my 10 when they went on.
 
ALMARTON said:
.

I am currently flying my RV9A Lycomming 160hp Hartzell on engine break-in (has only 38 hours yet) at 2400rpm , 24map and the most I can get out of this arround 8500ft is 163mph TAS. Is that normal/average for this rpm and map setting?

Another thing N941WR said that is safe to fly at 2700rpm is that true even at engine break-in period???

.
Click to expand...
I was taught that as long as you dont overheat it the break in period should be at as high a power setting as possible. Some people go so far as to start it on the runway for the first time, push all the knobs full forward and leave them there for an hour. It promotes rapid ring seating.
 
ALMARTON said:
Hi reading this topic got me to think I have something wrong...

I am currently flying my RV9A Lycomming 160hp Hartzell on engine break-in (has only 38 hours yet) at 2400rpm , 24map and the most I can get out of this arround 8500ft is 163mph TAS. Is that normal/average for this rpm and map setting?

I am asking that because I haven't yet tried 2500rpm (max map , full throttle) to get the 192-200mph folks here are describing.... how much power (in percent %) would this setting 2500rpm full throttle yield...? Is that safe for engine break-in period?

Another thing N941WR said that is safe to fly at 2700rpm is that true even at engine break-in period???

people that are reaching 192-200mph TAS what is you fuel consumption at that power setting? You fly that at 50F ROP or 100F ROP?

Much thanks for the responses because by now, I CAN'T GO ANY FASTER THAN 163 mph AND THIS POST LET ME THINKING maybe is just my lack of experience/knowledge yet... have to try other rpm and map settings....
Click to expand...

Something is not right with your numbers. I'd say you need to re-compute. Check out this thread: http://www.vansairforce.com/community/showthread.php?t=58513 I just posted some pics of my EFIS. You can see my numbers there.
 
Wax and speed....

All I can say is when my wings are waxed and so smooth that a cloth sheet slips off, the plane goes FASTER. I think it reduces the thickness of the boundary layer, thus less drag. I just know that it does make a noticeable difference.

At the canard RACE events, waxing the wings was common for that extra edge.
 
Here's a thought

Its really pretty simple. After takeoff, climb up to about 8,000 ft. That is where the engine will only put out about 75% power. To get the maximum speed, simply put the nose down. Its amazing how fast the plane will go:p

Tom,
RV-7A Flying
 
N941WR said:
Spin it faster. 2700 RPM is your redline, spin it up there as the engines are designed to run at the redline to TBO.

Remember that the standard Vans's recommended Sensenich prop has a 2600 RPM redline so be careful.
Click to expand...
 
typical top speed

Alexandre,
there are a lot of variables, not the least prop pitch.
If you have something like me, a Sensenich -79, and my top speed is about the same as yours. My old 0-320 will not rev over 2500 with this prop, so the top speed is similar to yours.
how all these guys are going 200 is also a mystery to me.
...maybe they mean kilometres per hour? :)
 
Thanks Mike S, Rick and apkp777 for the comments.

Well as I said I still not tried rev it up to 2500-2700rpm to see if I will get a speed increase, the best I used so far is 2400rpm with 24 map it gives me about 76% power in the EMS data.

I was recommended to use 2300 to 2400rpm with 24mp during break-in and I found through testing that 2350rpm with 24mp would give me 4mph (167mph TAS) more on final TAS than using 2300rpm or 2400rpm (163mph TAS)... so I would never guess that 2500 would/could yield speeds arround 180mph TAS as some here said... so after take-off I reved it down to 2400rpm and kept it there...

I will try it this weekend cruises at 2500 -2600 WOP (as I do not trust it to be safe to go to the 2700's redline continuously at all) and post results but I am not so confident that revs up to that would be so effective... lets see...

Another important detail... I am using HARTZELL propeller and noticed that many here uses Catto , would you bet that my poor performance is due to propeller or not using higher rpm and mp?

Thanks again!
 
Hello Flyboy, still a mistery to me also how to go to 200mph! :confused:

Forgot to say to count that my plane has all landing gear fairings set and is all properly finished and the drag should be equal to all the other RV's I think so it is not the issue as someone posted. :eek:

I use Lycomming 160hp 38 hours from new!

Hartzell propeller gets me to 2700rpm easily on take off (but not tried yet on cruise as said).

Will try... will see...and post.

Those 190-200's folks think I will succeed? Can't wait the weekend to see and tell. :cool:

Thanks.
 
ALMARTON said:
Hello Flyboy, still a mistery to me also how to go to 200mph! :confused:

Forgot to say to count that my plane has all landing gear fairings set and is all properly finished and the drag should be equal to all the other RV's I think so it is not the issue as someone posted. :eek:

I use Lycomming 160hp 38 hours from new!

Hartzell propeller gets me to 2700rpm easily on take off (but not tried yet on cruise as said).

Will try... will see...and post.

Those 190-200's folks think I will succeed? Can't wait the weekend to see and tell. :cool:

Thanks.
Click to expand...

It will require a bigger engine than a 320 160HP to get an IAS close to the 200 MPH mark in a RV9A doesn't matter what prop you're running. Ground Speed, well that's a different story and will depend on your winds.
 
Alexandre, you should get something close to 185 mph.

With you setup getting 185 mph should be an easy goal.
Go to around 8000 ft and push throttle and prop knobs full forward. You can't hurt your engine at that alt.

Do a three or four way GPS speed run to get a computed speed number.

Adjusting the mixture will allow you to max out the HP produced.

Kent
 
Hello LifeofReiley ,

Just to clarify things... I said that best I got so far is 163mph TAS when EFIS shows that speed I am normally reading 143mph IAS and GS at the moment would vary and is wind dependent...

I know it does not matter but I will say it anyway ... best GS I got so far was
205mph (ground speed ok!!!) and that moment I was on the same 163mph TAS and 143mph IAS...

My 205mph GS makes me a 200mph club's member? :D

Regards
 
ALMARTON said:
Hello Flyboy, still a mistery to me also how to go to 200mph! :confused:

Forgot to say to count that my plane has all landing gear fairings set and is all properly finished and the drag should be equal to all the other RV's I think so it is not the issue as someone posted. :eek:

I use Lycomming 160hp 38 hours from new!

Hartzell propeller gets me to 2700rpm easily on take off (but not tried yet on cruise as said).

Will try... will see...and post.

Those 190-200's folks think I will succeed? Can't wait the weekend to see and tell. :cool:

Thanks.
Click to expand...

Here's a thought - I notice both posters are from Brazil, and I know that Brazil likes ethanol in fuel (and as a fuel base) which raises the question - what is your fuel that you are burning?
 
Hi Airguy,

We in Brazil use ethanol as gasoline base ONLY for cars!! They are already designed and made for that as an enviroment / economical and political decison.

For airplanes we are not mad to use it when the engines are not suit for!

So mine and 99% of all piston aircraft here (experimental or not) uses nothing but pure 100/130 LL AVGAS.

Of course there are here some engines designed to use diesel and pure ethanol but it is not my case.

Thanks for the guess but is not the case...:(
 
good a step by step advice...

Hello Kentb,

I just read your post now ! It has escaped me before don't ask how...

kentb said:
With you setup getting 185 mph should be an easy goal.
Go to around 8000 ft and push throttle and prop knobs full forward. You can't hurt your engine at that alt.

Do a three or four way GPS speed run to get a computed speed number.

Adjusting the mixture will allow you to max out the HP produced.

Kent
Click to expand...

Two more things: 8000ft DA will do (speed and not damaging engine) or real 8000ft? Mixture adjusted to ROP 100F to get best power is that correct?

Thanks for the tip I will do just that this weekend and will post the results...

Can't wait to try :)
 
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Sorry Rick of Austin but I think I kind stole your topic... but so many doubts on best operation is a good cause for that and glad to get all the help.

I just remember some other thing is intriguing me. When I set the mixture to 100F ROP I always get the folowing in each cylinder:

1 - 103F
2 - 109F
3 - 78F
4 - 106F

I was wondering why number 3 is always getting hotter than the others and if this setting is good or I should rich it more to get something like this:


1 - 114F
2 - 127F
3 - 100F
4 - 119F

What would you folks with more experience say? What set is best and is there any potential problem with number 3 being always that hotter than the others?

Thanks again.
 
Vans numbers

Alexandre,

Just wanted to point out a couple of things. With your setup (160 hp/constant speed) Van's doesn't have performance numbers shown. However, the numbers should be close, they are based on a fixed pitch prop.

TOP speed listed is 197 mph, and that would be at sea level, wide open throttle. Your speed will only get slower from there as you climb. Solo weight at 8000 ft is listed at 189 mph. Based on these numbers, I doubt you will get 200+ mph with your setup.

Additionally, you are reading your true airspeed from your EFIS. Have you had your pitot/static system checked for leaks? Are you sure the EFIS numbers are accurate? The EFIS will calculate true airspeed based on density altitude and indicated airspeed. If your temperature sensor is wrong and/or your pitot/static system has errors, you could be going at a higher TAS than you are reading.

To tell for sure, do a 3 way GPS run and enter the numbers in the National Test Pilot School spreadsheet to determine TAS. A link to the spread sheet is available here.
 
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YES

ALMARTON said:
Hello Kentb,

I just read your post now ! It has escaped me before don't ask how...



Two more things: 8000ft DA will do (speed and not damaging engine) or real 8000ft? Mixture adjusted to ROP 100F to get best power is that correct?

Thanks for the tip I will do just that this weekend and will post the results...

Can't wait to try :)
Click to expand...

8000 ft DA and best power settings.
Use the spreadsheet in the post above to compute your results.

Have fun, Kent
 
ALMARTON said:
Hello Kentb,

I just read your post now ! It has escaped me before don't ask how...



Two more things: 8000ft DA will do (speed and not damaging engine) or real 8000ft? Mixture adjusted to ROP 100F to get best power is that correct?

Thanks for the tip I will do just that this weekend and will post the results...

Can't wait to try :)
Click to expand...

Due to ram air effects of the efficient induction system of the RV's you'll probably need to fly higher than 8000 ft DA to get the output of the engine below 75%. Plus, if you have a Sensenich prop, you will exceed the prop RPM limit.

In my 9A, I found that 10000 ft DA was closer to the 75% power level.

Vern
 
Hi folks,

As promissed finally let me update this post with my results/tests after this first sunny weekend here...

I tried WOP (wide open throtle - full throtle) , full rich, 2650rpm (Hartzell) in my RV9A with Lyc 160hp and the max I got was 159mph IAS (that gave me 186mph TAS). EFIS was reading 91% power (think it would never got to 100% though cause I was already full throtle...)

That was maximum speed I got level flight (8000ft DA).

Thanks all for the comments and tips, regards;

Alexandre "neck" Marton
 
That is going to be very tough I suspect

There are a lot of things you can do to reduce drag beyond the stock completed airplane with all of its fairings. In my RV-6A the initial tested three direction maximum baseline speed at 6000 ft density altitude was 170.67 kts. I have tried a lot of things and reported them in this forum. Many did no good or even reduced the speed. The top speed I have been able to achieve is now 184.4 kts.

Bob Axsom
 
Neck, you plane is looking good.

ALMARTON said:
Hi folks,
I tried WOP (wide open throtle - full throtle) , full rich, 2650rpm (Hartzell) in my RV9A with Lyc 160hp and the max I got was 159mph IAS (that gave me 186mph TAS). EFIS was reading 91% power (think it would never got to 100% though cause I was already full throtle...)

That was maximum speed I got level flight (8000ft DA).
Click to expand...

The EFIS power table should be adjusted. With those setting the power indictation is to high. I don't know the correct formula, but I would think something around 75 - 80 percent power.

Kent
 
On my 9A, I went from 188 to 192 WOT when I put on the second P-Mag. The first one cut my fuel burn, but didn't increase the performance noticeably. When I added the second one, it didn't cut the fuel burn much , but added about 4 mph top. This was with a waxed plane, and I can see a difference, although I haven't done any serious measurement.

Bob Kelly
 
ALMARTON said:
Hi folks,

As promissed finally let me update this post with my results/tests after this first sunny weekend here...

I tried WOP (wide open throtle - full throtle) , full rich, 2650rpm (Hartzell) in my RV9A with Lyc 160hp and the max I got was 159mph IAS (that gave me 186mph TAS). EFIS was reading 91% power (think it would never got to 100% though cause I was already full throtle...)

That was maximum speed I got level flight (8000ft DA).

Thanks all for the comments and tips, regards;

Alexandre "neck" Marton
Click to expand...


Full rich @ 8000ft DA will cost you some power; leaning for "best power"/slightly rich-of-peak will get it back for you if your engine is broken in and otherwise able to run there.
 
Wasting Fuel

ChiefPilot said:
Full rich @ 8000ft DA will cost you some power; leaning for "best power"/slightly rich-of-peak will get it back for you if your engine is broken in and otherwise able to run there.
Click to expand...

Plus = Full Rich - WOT at 8000 feet will certainly waste a lot of unburned fuel and leave you a black smoked belly and maybe some fouled plugs :mad:
 
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