David-aviator

Well Known Member
Would you believe, 61F in St. Louis on January 9, 2009, clear skies and almost no wind! And not only that, I finally got all the ducks lined up with regard to installing the Barrett Lycoming IO360-X, AFP fuel injection system and Catto prop. What a break with this beautiful day - it was time to launch. With neighbors John and Gloria Roser flying chase in their RV-6A, N707DD took to the air for the first time since July 17 when it was grounded for the engine change from the Subby H6.

The flight was almost uneventful with oil temp topping out at 170F and the highest CHT observed to be 348F. The engine with the Catto 3 blade prop is almost as smooth as the Subaru. This was an engine break-in flight so not much happened for 30-40 minutes running at about 75% at 4500'. Observed fuel flow was like 19 gph so for sure the EIS 4000 flow sensor needs a different calibration number than 200, the engine can not be burning that much fuel.

But when both tanks got down to about 7 gallons, I decided to make for the barn. John and Gloria were standing by at 2500' taking pictures of the sun set when I commented I can't get this thing to slow down. Fixed pitch verses constant speed prop makes for a completely different flying experience. Finally I got it back 80 knots and lowered 20 flaps and on final went to 40. Problem was, I was a bit high to clear the trees on the west end of our 2200' runway and even with idle power the thing accelerated to 85 knots from about 70 real quick when I did the usual dump over the trees and I decided this is not going to work so power up to go around. On the go the flaps retracted to about 15 and that was it. The flap motor failed! Well, long story short, it took 3 approaches to finally get the thing lined up, on speed, clear the trees, not accelerate and land. What worked was coming in low and slow at 70 knots with a little power, not dump it over the trees but make a constant on speed descent to the touch down point at about the 1500' foot mark on the runway. The airplane was easily stopped in about 1000' even with the slightly melted frost grass surface.

Not much more to say about the flight except the take off performance definitely was anemic compared to the H6 and the MT constant speed prop. With this engine I am experimenting with a direct un-filtered ram air intake, but I don't have the nerve to use it on the ground yet, so it was filtered air from inside the cowl for take off. Once I got to about 1000' AGL I slowly opened the ram air inlet and closed the filtered air intake. Wow! RPM went up from 2250 to 2450 like right now. The airplane felt like it got a kick in the butt, it do make a difference. I'm undecided whether or not to stick with this internal filtered air set up but I guess I can think about it while fixing the darn flap motor.

Beyond that, it sure is good to be flying again. :)
 
I don't know what the auto engine horsepower was but constant speed prop to fixed pitch may be most of the difference.

Funny about not being able to slow it down. You just have to approach the pattern differently. Coming in full power and expecting to be at the right airspeed on final won't happen.
 
Congrats David, I've been following your progress all the way from me having many tens of thousands of dollars in the hands of a subaru seller. The lycoming is really something if you can wind it up to the rated 2700 rpm on takeoff. It makes me smile every time... Great to see you back in the air.

Cheers,
Scott
 
David,
Good to see you back in the air again. Looking forward to your synopsis of Lyc vs Subbie once you get accustomed to the new power plant.
Good luck,
 
Congratulations Dave! I've been following your progress since we both had car engines in our airplanes way back when. Glad to hear you're back in the air!

mcb
 
Welcome back

David,

Congrats and welcome to the Lycoming world! As you know I flew the Subie EJ25 RV-7A as my first build. My new RV7A is Mattituck TMX IO-360 with horizontal induction. The take-off (and cruise) performance doesn't even compare.

Glad to hear everything is well! Your determination over the past few years has been impressive.

Steve Hurlbut
7A Flying
 
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Glad to hear you are back in the air David.:)

The fixed pitch RVs I've been in certainly lack takeoff and initial climb performance compared to variable pitch/ CS ones but cruise should be good once you get it wound up. The Lycoming probably has a lot more residual thrust at idle compared to the Sube so that may take some getting used to.

Will be interesting to see the comparison numbers in the same airframe once you get everything sorted out.
 
Congratulations David - glad to hear that you have it back together and flying!

Fixed pitch? Yup - welcome back to the world of slippery airplanes.....;)

Paul
 
Do you have pictures of your ram air setup?

Yes. as of this morning.

I can not recommend this set up just yet. It came about because the bottom cowl had a large hole where the Subaru oil cooler was located and it had to be closed plus I had to accommodate the FM-200 fuel controller - so one thing lead to another.

I spent a week building the intake to match the "Y" attachment to the FM-200. The attachment comes with one or two butter fly valves. With one valve at the intake, when it is open ram air can flow back through the filter into the engine compartment, so I opted for the unit with 2 valves. When one is closed, the other is open. The image shows the straight-in unfiltered duct in the closed position.

The cowl has had several major modifications in an attempt to solve H6 engine cooling issues and nothing really worked, so here I am using the same cowl (rough as it is) with the Lycoming. (The EGG factory has gone to larger radiators and a special cowl for much better cooling)

I will make several more flights to record some performance numbers and then decide what to do next. I could very well be that the Vans snorkle, modified for the FM-200, is the best way to go. If the numbers are respectable, I will clean up and finish what I have, if not, I may opt for a new cowl and start over. This cowl had to be moved aft and to the left to accommodate the Lycoming center line so it is more than a little rough right now.

[img=http://img187.imageshack.us/img187/127/afp2is9.jpg]
[img=http://img187.imageshack.us/img187/afp2is9.jpg/1/w384.png]




 
I fly with a three blade Catto and have found the best way to slow the thing down is to lower the engine rpm to minimum safe. I idle at 400 on the ground but rarely pull it back that far except on final. When I lowered the rpm from 650 to 400 it made a BIG difference in sink on final. Not as good as a CS, but much better control. In over 100 hours, there has never been any tendency to do anything improper, like quit or fail to react to throttle changes. I would wait until the engine is broken in, then start backing off on the rpm. WMMV. BTW, the engine is smooth at 400, once warmed up. Your compressions should be equal or very close or that may not happen.

Bob Kelly
 
Cool welcome back

I don't think I would use unfiltered air on the ground but I do think you need to go to the van's snorkel set up.

As others have said there is a big difference when you can't get the RPM up to 2700.

But once you have broken in you should be getting around 160kts at 7 to 7.5GPH running LOP on autofuel....Hard to argue with that!

Frank
 
Yes. as of this morning.

I can not recommend this set up just yet. It came about because the bottom cowl had a large hole where the Subaru oil cooler was located and it had to be closed plus I had to accommodate the FM-200 fuel controller - so one thing lead to another.

If you are gaining 200 RPM in level flight just changing between air sources, it sounds like that small filter is choking the engine quite a bit.
 
If you are gaining 200 RPM in level flight just changing between air sources, it sounds like that small filter is choking the engine quite a bit.

Yep, that thought has occurred to me also. The engine turns up 2150 static easily on the ground on air through the filter but in flight it will need more air and it may not be getting it.

This K&N filter is the smallest they make with an attach opening of 3.5" and is just 3" long. The unit AFP uses is 4" long but I couldn't fit it in that area without going remote with scat tube. (the AFP 4" unit is used on 6 cylinder engines so I thought the 3" might work) Before next flight I will remote mount a much larger filter and see what happens.

After some thought (while fussing with the no good flap motor) I still like the idea of direct ram air intake in flight and the engine has got to like it also. If I can get satisfactory take off performance with a larger filter, I may just stick with it.

From an air flow perspective, internal cowl air is heated and less dense than air from the left intake area (as per the snorkle) but it is going to a cold air sump and may well be a wash item compared with the standard Lycoming oil heated sump. Also, pulling air out of the lower cowl area will lower the pressure there and perhaps facilitate better flow of cooling air from top through the cylinders. We shall see.

The flap motor has perished. It is a Motion unit built in 2001 and failed once before. I cleaned it up and has worked since but no more. I took it apart, cleaned it again (it was not dirty) put it back together and applied power. It ran the shaft in and out a couple time and I though "great" and then the motor began to emit a blue colored smoke. I took it apart again, looked things over, reassembled it and tried it. This time it didn't run at all.

I have no ideas on what to do next except call Motion in NJ tomorrow.
 
Hi David,

I fly out of a shorter strip that that with trees on it, and had a FP RV6 for a long time. Don't forget...these RV's will lay over on their side perty as can be - no reason not to slip 'em (and slip 'em hard). You can drop like a rock a'la your "dump over the trees" quite easily without gaining a speck of airspeed. Lay the thing over on it's side and down you go! Poor mans spoiler system!

Also, as others if have said with that large of an RMP increase just by opening the ram air something is way wonky.

Congratulations on flying. If you were to hang a C/S on the front of that thing you'd really be amazed! What are you going to do with all the extra time you'll have now not dinkin around with your FWF setup??!?!?! :)

Cheers,
Stein
 
Hi David,

I fly out of a shorter strip that that with trees on it, and had a FP RV6 for a long time. Don't forget...these RV's will lay over on their side perty as can be - no reason not to slip 'em (and slip 'em hard). You can drop like a rock a'la your "dump over the trees" quite easily without gaining a speck of airspeed. Lay the thing over on it's side and down you go! Poor mans spoiler system!

Also, as others if have said with that large of an RMP increase just by opening the ram air something is way wonky.

Congratulations on flying. If you were to hang a C/S on the front of that thing you'd really be amazed! What are you going to do with all the extra time you'll have now not dinkin around with your FWF setup??!?!?! :)

Cheers,
Stein

Yep, again. :)

I was talking to friend today about slipping the beast in and he said on his RV-6A check out it was demonstrated and it will come down like a rock. That little procedure I will work on.
 
Flying Again

David:

I've followed your travails over the years and am so happy that you're back in the air again.

I have tremendous respect for you guys who pioneer new engine ideas and other concepts that further the idea of "experimental".

You have my best wishes going forward into sorting out the problems that you're facing now. I have no doubt that that you will overcome them all!!!!!!!!:D
 
Congratulations Dave! Figured the fixed pitch prop would not match the MT electric on climb-out but hope it will make up for it in cruise, since that is where we fly most. I'm 5 months behind you in changing from Subie 2.5L to Lycoming but progress is good. Fun to be building again! Spent the weekend Trimming the cowl... Plan to be flying in April.