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RV-8R second test flight prelim data.

flyboykelly

Well Known Member
We had a successful and event free test flight number two today!!! Prelim numbers show a cruise speed of 155mph at 23" of mp and 3000 engine rpm. This is 15 mph faster than my initial design goal. This is also only 15 mph slower then my fathers 200hp RV-8. These speeds would not have been possible without the use of the GT electric prop. After shutdown I laser checked the cylinder head temps. None of them were over 200f. The baffling is doing its job quite well! Time to de cowl and do a visual inspection and filter check. Video is posted below.

http://youtu.be/fSLpesAVVuw
 
My only beef with these videos is that it was -12C here this morning and seeing those palm trees and sunshine is annoying :p

I love the look and sound of that airplane! I'm jealous...
 
We had a successful and event free test flight number two today!!! Prelim numbers show a cruise speed of 155 mph at 23" of mp and 3000 engine rpm. This is 15 mph faster than my initial design goal. This is also only 15 mph slower then my fathers 200hp RV-8.

155 MPH, or 155 knots?
 
Radial benefits...

all cylinders should theoretically get equal and instant cooling when airborne if baffling is working properly...they just like to leak a "little oil" in the bottom cylinders...I miss the Wright radials we had on the S2F,Wright R-1820-82WA radial piston engines developing 1,525 horsepower each...:p
 
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I am not seeing a lot of 200hp RV8's cruising at 3000 rpm and only hitting 170 mph. Just sayin'. The -8 you are comparing to must be a monster dog. Not taking anything away from your radial - that thing looks awesome!
 
I am not seeing a lot of 200hp RV8's cruising at 3000 rpm and only hitting 170 mph. Just sayin'. The -8 you are comparing to must be a monster dog. Not taking anything away from your radial - that thing looks awesome!

150hp and a bit more drag = a slower airplane than a 200 hp RV.

But guess whose airplane everyone will be standing around at Oshkosh? ;-)
 
I am not seeing a lot of 200hp RV8's cruising at 3000 rpm and only hitting 170 mph. Just sayin'. The -8 you are comparing to must be a monster dog. Not taking anything away from your radial - that thing looks awesome!

The numbers I'm comparing to are 75% cruise numbers. But I also did a lot of aero work on the radial rv that I think helps. So it's hard for a true side to side comparison. I'm not measuring fuel flow yet (not until the efis is installed). All I know is I needed to satisfy one person with this project and I'm VERY satisfied!

I'll keep everyone up to date on the performance dats as testing continues.
 
The numbers I'm comparing to are 75% cruise numbers. But I also did a lot of aero work on the radial rv that I think helps. So it's hard for a true side to side comparison. I'm not measuring fuel flow yet (not until the efis is installed). All I know is I needed to satisfy one person with this project and I'm VERY satisfied!

I'll keep everyone up to date on the performance dats as testing continues.

Very nice accomplishment on the radial. Congrats!
But I'm sure there are a lot of us that are scratching our heads about a 200 hp RV8 that's cruise speed at 75 % pwr is only 170 mph.

We have a lot of RV8s in Cincinnati that cruise at well documented and verified 170 KNOTs at around 60%pwr, with parallel valve IO 360s.
 
That things sounds amazing! Thanks for the video.

That big radial and associated cowling no doubt has more drag, which goes a long way toward explaining the lower cruise speed. Totally worth the trade....you've created a unique and wonderful machine.
 
Speeds

Heck...........who cares how fast it goes! If I built and was flying that airplane I wouldn't be in any hurry to reach the destination ;)

Great job on the build.
 
That things sounds amazing!

Precisely.... love the sound.

That big radial and associated cowling no doubt has more drag, which goes a long way toward explaining the lower cruise speed.

Brian, considering just firewall forward, do you know how much additional frontal area you actually have?

The frontal area of a stock RV8 might be considered the firewall area plus that part of the coal shovel cowl exit which extends below the belly skin line. The Rotec is only 33.5" diameter, so I'm guessing the cowl is not wider than stock.
 
Precisely.... love the sound.



Brian, considering just firewall forward, do you know how much additional frontal area you actually have?

The frontal area of a stock RV8 might be considered the firewall area plus that part of the coal shovel cowl exit which extends below the belly skin line. The Rotec is only 33.5" diameter, so I'm guessing the cowl is not wider than stock.

Dan,
Some quick and dirty calculations based on the CAD drawings Van's has available on their website:

Frontal area of the RV8 as you described: 6.87 square feet...assuming the Van's CAD drawings are accurate.

Frontal area of the radial cowl, assuming 38" diameter at it's widest (that's only 2" clear all around): 8.48 square feet....a 23% increase over the 8.

If we can shoe-horn the radial into a super-tight fitting cowl...say 36" diameter (1" clear all around), that's 7.07 square feet....or only a 3% increase.

Brian,
Not picking on you or your airplane...just an academic exercise with Dr. Dan, because he has that affect on me (he makes me think!)... :D
Congratulations on a job well done! Your airplane is gorgeous, and giving me a bad case of the wants.
 
Precisely.... love the sound.



Brian, considering just firewall forward, do you know how much additional frontal area you actually have?

The frontal area of a stock RV8 might be considered the firewall area plus that part of the coal shovel cowl exit which extends below the belly skin line. The Rotec is only 33.5" diameter, so I'm guessing the cowl is not wider than stock.

The firewall is stock between the longerons. All I did was raise and lower it a little bit. I got the original idea to do the conversion because the diameter of the engine was very close to the width of a lycoming. To I was able to use the stock Vans hard points and didnt need to re engineer the airframe. So other than the opening for engine cooling, the flat plate drag isn't to much higher. In the future when I install an efis and can got more data on engine cooling, I may install a larger spinner and close down the gap a bit to gain some additional speed.


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Dan,
Some quick and dirty calculations based on the CAD drawings Van's has available on their website:

Frontal area of the RV8 as you described: 6.87 square feet...assuming the Van's CAD drawings are accurate.

Frontal area of the radial cowl, assuming 38" diameter at it's widest (that's only 2" clear all around): 8.48 square feet....a 23% increase over the 8.

If we can shoe-horn the radial into a super-tight fitting cowl...say 36" diameter (1" clear all around), that's 7.07 square feet....or only a 3% increase.

Brian,
Not picking on you or your airplane...just an academic exercise with Dr. Dan, because he has that affect on me (he makes me think!)... :D
Congratulations on a job well done! Your airplane is gorgeous, and giving me a bad case of the wants.

Your second diameter would be the correct one. There is about a one inch gap between the engine and cowling all around. Thanks!
 
Yep

, I may install a larger spinner and close down the gap a bit to gain some additional speed.


Exactly what Darryl Greenamyer did with his Bearcat. He also filled in the rounded intake lip inside the cowl to reduce turbulence there and has a really small gap between the spinner and the cowl intake...lots of drag reduction possible there.

Beautiful RV you have,
 
I love your unique RV-8R! It looks and sounds like no other RV out there!

I looked at the 1st flight video you posted on Facebook and could not read clearly the ASI. However, it looks like you are reporting IAS, not TAS. Is that correct? Anyway, speed is secondary when you have a great looking and sounding airplane like that.

Can't wait to see and hear it in person some time!

TJ
 
The only person who will feel the speed difference is you. But on the ground? Man, you will need to put up an electrified cattle fence around that thing at Oshkosh to keep all the drool off of it. Mucho cool!
 
I love your unique RV-8R! It looks and sounds like no other RV out there!

I looked at the 1st flight video you posted on Facebook and could not read clearly the ASI. However, it looks like you are reporting IAS, not TAS. Is that correct? Anyway, speed is secondary when you have a great looking and sounding airplane like that.

Can't wait to see and hear it in person some time!

TJ

All of the speeds are IAS @1000 agl.
 
A long time ago, when such things were not censored by the current regime of political correctness, I had the opportunity to fly with a true greybeard bush pilot. His leather flight bag was battered and bruised from its many years of being stuffed in whatever spare space could be found in the long list of airplanes this man had flown. In conversation I learned that one of his most prized possessions was a rare sticker on that flight bag, purportedly supplied by Pratt & Whitney. I couldn't help but smile when I read that sticker:

"REAL MEN FLY ROUND ENGINES"

Your RV8R ranks right up there with the hairy-chested, manly-men's airplanes of yesteryear - the Grumman "cats", the Bull Stearmans. You have every right to stand beside your machine and beam with pride, knowing you have built something totally unique, something which earns you the envy of so many who would not have dared embark on such an ambitious project.

Go fly her for the sheer joy of flying an airplane with a round engine, and know that, on the ground below you, men and women, both young and old, are looking up and feeling the goosebumps form as they delight in the throaty rumble of your radial.
 
In the future when I install an efis and can got more data on engine cooling, I may install a larger spinner and close down the gap a bit to gain some additional speed.

For now, fly some three-leg airspeed calibration runs. After some hot weather testing, throttle the exit. The big hole in the front is just a low Vi/Vo intake.
 
Brian,

Your plane is not about top speed. It's about being something very new and exciting. It epitomizes the spirit of E-AB flying and building. No, your plane doesn't and will never match the speed and narrow expectations of those who only appreciate this facet of the RV world. But you do have a plane that will draw the interest of pilots with any minimal knowledge of light GA and experimenting. People will walk right by the fastest Lyc powered RV to come see your plane. Enjoy it for what it is. A very cool looking, very cool sounding, radial powered RV.

Hope to see you and your plane at a fly-in one day!
 
A long time ago, when such things were not censored by the current regime of political correctness, I had the opportunity to fly with a true greybeard bush pilot. His leather flight bag was battered and bruised from its many years of being stuffed in whatever spare space could be found in the long list of airplanes this man had flown. In conversation I learned that one of his most prized possessions was a rare sticker on that flight bag, purportedly supplied by Pratt & Whitney. I couldn't help but smile when I read that sticker:

"REAL MEN FLY ROUND ENGINES"

Your RV8R ranks right up there with the hairy-chested, manly-men's airplanes of yesteryear - the Grumman "cats", the Bull Stearmans. You have every right to stand beside your machine and beam with pride, knowing you have built something totally unique, something which earns you the envy of so many who would not have dared embark on such an ambitious project.

Go fly her for the sheer joy of flying an airplane with a round engine, and know that, on the ground below you, men and women, both young and old, are looking up and feeling the goosebumps form as they delight in the throaty rumble of your radial.

AMEN!

For those of us who have been around a while, aviation has come a long way leaving us with sights, sounds and smells in memory only, except maybe at OSH when the War Birds do their thing.

A few years back I shook hands with Gunther Rall at OSH the year before he passed away, it was like shaking hands with history, the same hand Adolph Hitler grasped several times as Rall was awarded another metal for his feats during the war. His life was complicated in that his wife was under constant scrutiny by the SS because she helped a Jewish family escape arrest.

Anyway back to the round engine RV-8, I think its a great accomplishment. As Brian said yesterday, I did it to please myself - and you've also pleased others just by doing it. :)
 
"REAL MEN FLY ROUND ENGINES"

Your RV8R ranks right up there with the hairy-chested, manly-men's airplanes of yesteryear - the Grumman "cats", the Bull Stearmans. You have every right to stand beside your machine and beam with pride, knowing you have built something totally unique, something which earns you the envy of so many who would not have dared embark on such an ambitious project.

Go fly her for the sheer joy of flying an airplane with a round engine, and know that, on the ground below you, men and women, both young and old, are looking up and feeling the goosebumps form as they delight in the throaty rumble of your radial.

The above comments really resonate deeply. While there's something magical about any airplane a round-engined plane is just something else. Who needs speed when you get a huge plume of smoke with every start and admiration with every turn?

Big congrats (even makes the lurkers come out)!
 
My first flight complete!

Test flight number three is complete! This was my first flight in the airplane, and all I can say is WOW! That thing is a lot of fun! A problem has crept up with the prop governor. It doesn't want to go to high pitch in cruise. So I'll work with flybox to fix that issue. Also I'll need to add an air oil separator as I had quite a bit of oil coming out of the breather. All of these are normal developmental issues. The Rotec Aerosport R-3600 is running great! Once these two items are fixed flight testing will resume.

Video posted below.

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http://youtu.be/FTtgIse4t1A
 
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Electric prop

You may want to consider running the pitch of the prop manually. We Subie pilots have alot of experience with electric props. The automatic modes have had problems with keeping up to rapid throttle changes and you can end up with engine over speeds and lack of performance on go around. A manual mode also saves wear and tear on the pitch mechanism since you only change pitch a couple of times each flight.

We set the fine pitch stop to be like a climb prop giving max RPM at about 120 mph with full throttle. We set the course pitch stop to give desired RPM at cruise speed. This way the pitch is never outside a usable range. I have a bright LED that comes on when the electic motor hits the stop (it senses the stalls current from the motor). I could use a finer pitch stop for better take off but I don't need more and I like to keep my engine RPM down for longevity.

-Andy
 
Brian,
Your plane is not about top speed.

Seems we have a recurring theme here. Ya'll quit apologizing like the family does for a ditzy cousin ("...but she is such a sweet girl"). ;)

No thinking person expects the 8R to be fast. After all, it's only got 150 HP. However, I'd bet the next Oshkosh beer tab that it will go faster with a bit of development. And God knows, none of us need an explanation as to why it is cool.
 
My wife and I got the chance to see this wonderful machine up close and personal. All I can say is "WOW", this is one impressive build. THANKS for reminding all of us what EXPERIMENTAL aviation is all about.

EAA%20288%20Jan%20Meeting_zpsmbbbfriv.jpg


:cool:
 
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Brian - Congrats on getting that beautiful aircraft flying. It was great to see the project in 2014, and I'm looking forward to seeing the completed aircraft at SNF or OSH.

Good luck with the flight test program.
 
Round Engine Lament

Supposedly written by a Navy Corsair or Hellcat Pilot on transition to Jet aircraft:

DEDICATED TO ALL THOSE WHO
FLEW BEHIND ROUND ENGINES

We gotta get rid of those turbines, they're ruining aviation and
our hearing...

A turbine is too simple minded, it has no mystery.
The air travels through it in a straight line and doesn't pick up
any of the pungent fragrance of engine oil or pilot sweat.

Anybody can start a turbine. You just need to move a
switch from "OFF" to "START" and then remember to move
it back to "ON" after a while. My PC is harder to start.

Cranking a round engine requires skill, finesse and style. You
have to seduce it into starting. It's like waking up a sleepy mistress.
On some planes, the pilots aren't even allowed to do it...

Turbines start by whining for a while, then give a lady-like poof
and start whining a little louder.

Round engines give a satisfying rattle-rattle, click-click, BANG,
more rattles, another BANG, a big macho FART or two, more clicks,
a lot more smoke and finally a serious low pitched roar. We like that.
It's a GUY thing...

When you start a round engine, your mind is engaged and you can
concentrate on the flight ahead Starting a turbine is like flicking on
a ceiling fan: Useful, but, hardly exciting.

When you have started his round engine successfully your Crew
Chief looks up at you like he'd let you kiss his girl, too!

Turbines don't break or catch fire often enough, which leads to
aircrew boredom, complacency and inattention. A round engine
at speed looks and sounds like it's going to blow any minute. This
helps concentrate the mind!

Turbines don't have enough control levers or gauges to keep a pilot's
attention. There's nothing to fiddle with during long flights.

Turbines smell like a Boy Scout camp full of Coleman Lamps.
Round engines smell like God intended machines to smell.
 
Awesome. Best looking RV out there no exaggeration. 155 on 150 hp is very impressive! Mine only does 110mph on similar power.

Time to change your signature. I'd love to see some high def videos in landscape. Good luck in your continued development.
 
We had a successful and event free test flight number two today!!!
<snip>
Video is posted below.
http://youtu.be/fSLpesAVVuw

Congrats! That has got to be the most wicked-sounding RV on the planet!
I love how on start-up, a few of the construction workers in the background stopped what they were doing - you know you've done something special with an airplane when non-aviation folks stop & stare!
 
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