RBean

I have a VQ P-40 that is a good flyer with Magnum .91 FS, just don't fly it much. Out of glow fuel, glow plug dead, glow starter not charged, messy after flying. Plane has Lado electric retracts, repositioned to scale location. Had a DLE 20 which Santa brought. Decided to see if I could Shoe horn this thing into 63" wing span warbird. Had to cut out fire wall for carb breathing; 2nd had to change throttle servo from fore and aft to sideways to gain 1/2" to move fuel tank back. used smaller 12oz tank. choke control out the front; left top open so carb could get air; air duct from top scoop back to carb area.

RBean

I was planning on using a J-Tec compact pitts muffler, but it wouldn't fit. I don't like that hot exhaust can right under the carb any way. So I have fashioned my home made exhaust system. Hope it works. I had acquired a hedder block from Virginia RC Models for another project. Use it. It has 5/8" dia. aluminum tube threaded to screw into hedder. It is straight. Cut off to miminum length and attached 45 degree brass coupler with hose clamps then another short tube clamped on. The 11/16 in dia. tube that slips over the smaller, silicone tube to seal, support bracket in rear with springs to keep it from backing out. Don't know if it will work or hold up. I hope the exhaust turning 90 degrees and then 45 degrees quiets it down some. 16-8 three blade M/A prop. Engine is completely enclosed, nothing sticking out. Don't know if I need the cut out on bottom of cowl or not for exit air. My scale broke but I think weight increase is about 10oz. Total weight about 10 lbs. I'll test run on ground w/o cowling and see if exhaust system holds up. I'll report on test flight if we have any good weather where I can get in a flight.

a1pcfixer

My Feedback: (7)

Cool setup there, especially like the exhaust extension!

Couple items you might upgrade though;
TH cheapo servos might not last long in a gasser, and I highly recommend that you put nuts on the eng hold down bolts.
Good airflow over the cylinder head cooling fins is a must. Might find you need to open that up a bit.

BR1

I put a DLE20 in my Hanger 9 P40 no mess, no cooling problems, no worry love it. Vertices's to die for.

FentonFlyer

My Feedback: (11)

Get rid of that metal clevis on your choke.

RBean

FentonFlyer,

Why get ride of the metal clevis in the choke? I have another plane set up that way with 150 flights on it with no problems. What am I missing? Using Futaba 2.4 radio. a1pcfixer, thanks, about the servos. Didn't even think about it. I have a couple of metal geared up market servos I'll use for the rudder and elevators.

acdii

What the heck happened to your muffler? Looks like it melted!

3136

Hi RBean, looking good, I have that plane with a fs 91 too.
There is something about the P40, you just have to love it.
How have you found the lado gear?
Could you elaborate on that header block?
They are a heavy plane already, I will be interested to hear your flight reports.
(Mine is a little heavier than most due to extra ply and fibreglass from a crash rebuild)

Regards Mark

RBean

Mark,

I got the hedder from http://vamodelbuilders.com/index.html . The retracts are the old Lados. About 3 yrs old. I had to drill them out to take 3/16" rods so they would hold up. So far ok. The plane will weight about 10 lbs. I have heard of other people who live at high altitude location having OS 120 FS engines in VQ P-40s. They would weight almost the same and they reported landing speeds only slightly higher but otherwise flew fine. We will see. Also I like the fact that I can use a 16-8 three blade prop that is close to scale size.

I'm hoping my exhaust system will hold up. I'm concerned the copper 45 degree elbow might crack or the silicone not last. Will test run this week end and find out.

The VQ flys much better than my Top Flite P-40. It just needed a gas engine.

RBean

That is a kit built Top Flite P-40. I understand the new ARFs do better.

3136

Hi RBean, you could always try and see if slanting the motor will help, you may be able to use the stock exhuast. (Sorry to tell you after all the effort you have been through).
I did this with a world models Mustang fitted with a dle 30. It wouldn't fit in the normal vertical.
I didn't want to demolish the cowl so I slanted it around and fits fine, you don't notice the small exhaust pointing on an ange when it flies.
Regards Mark

RBean

3136, I tried canting over but wouldn't work, top of muffler hit cowling and plug boot wouldn't fit completely inside. In fact the 91 fs I took out was canted so the in cowl hedder pipe would not contact cowling. If my exhaust pipe works, no problem. If not I'll have to try something else. Looks like a snow storm here this week end so may not get to test run.

RBean

I finaly got a chance to test run the engine. Ran without the cowling. started and ran ok. Idle about 1,680 rpm. Max about 7,280 rpm. This is because it has the "new" Master Airscrew 16-8 three blade which appears to have more pitch out towards the tip the the older model. Same engine turns the old model 16-8 3 blade about 8,300 rpm. No matter, will still be more than enough power for this plane. Only needed small needle adjustments and after two runs it appeared the exhaust system is holding up. Too windy to fly. I'll test run again with the cowling tomorrow and maybe test fly if the weather is ok. But I think high winds are forcast.
A little loud but shouldn't be too bad out on the runway and in the air.

RBean

Ran it again today with the cowling on. No problems that I can detect. Too windy to fly, especially a test flight. Quartering cross wind 15mph. Too much for me flying plane with retracts.

RBean

Finally had a day with light winds. Got to test fly. Take off was good and only a few clicks to trim. Seemed slightly touchy in pitch but not bad. Has plenty of power and good verticle, but not unlimited. I think the engine is slightly over propped with this "new" M/A 16-8 three blade. Did an approach stall, gear and flaps down, flew quite slow, then with the break, dropped left wing 90 degrees and headed straight down. Normal P-40 stall. Did tight turns and small loops, it had not tendency to snap out. On pull up didn't twist to right. Good flying. I did three flights and had three good wheel landing. Probably lands slightly faster than before ok. In fact seems less touchy on landing than before.

RBean

I got to fly again today. Just to see what the difference would be, I replaced the "new" version MA 16-8 three blade prop with and old one. Turned the new one 7,300 rpm. Turns the old one 8,500 rpm and verticle is now almost unlimited. Low speed thrust is better and level speed not any slower that I can tell. The old MA 16-8 three blade is the perfect prop for this engine in a warbird. I think the engine is a little over proped with the new version. Don't know why MA changed the specs. Didn't they ever hear "don't fix what ain't broke"?

Thunderbolt47

My Feedback: (8)

Hey RBean, I didn't know MA changed their prop. I just received two 16x8s. I will run the engines tomorrow with these props. I've been running them with an APC 17x6 2 blade. They both hit 9100rpms with this prop.
Kelly

RBean

Let me know how it goes. The "new" Master Airscrew 16-8 three blade prop has "4120T" on the blade. Hard to believe 1,200 rpm difference, but that is what I got with the tach and you can tell the difference flying. The next smaller size down for three blade MA is a 15-7. I don't want more than 8,500 rpm static because with the engine is "unloaded" at high speed, I've been told you get an extra 1,000 rpm. I think the 15-7 would be too small, too much rpm in flight. Tried to find a Graupner 15-8 or 16-8 three blade. Nobody has any that I can find in the US

raydar

The graupner 15 8 3 blade does seem to be the 3 blade prop that works best, my rcg 20 beam mount gets 7800 rpm with it, and 12 pounds static thrust which is down on a xoar 17 6 but to be expected with a 3 blader.

Forget the graupner 16 8 3 prop for the 20cc I have one and it spun 7400rpm, it will work better in a dle 30, my crrc 26 v1wont even spin it, but then again it is not as strong as the rcg 20.

Master airscrew need to update there 15 8 3 as well for the 20 cc gas market.

3136

Good stuff  Rbean, what was your AUW?
I have a fs 91 in mine, with the extra plywood and glass from crash repairs it comes in at 4.3kg.
It feels like a heavy model for the wing size, but the bloody thing flys really well!!
I'm always surprised at how slow it can come in with 50% flaps.
Mine looks a hell of a lot more beaten up than yours though.
It looks like the dle 20 is ideal for this plane, thanks for doing the groundwork.
I'll put that on my list.

Regards Mark

RBean

3136,

I had to convert to lbs. 4.6 kg = 10.14 lbs. My P-40 weighted 4.2 kg before conversion and now 4.6 kg or 10.2 lbs. afterwards. So mine is the same wtg as yours is now. So if the wtg increase is .4 kg your's might be too heavy. Of course there are things you can do to save wtg. Use a lipo for both ign and radio with voltage regulator etc would save the weight of one battery. I'm using two, a 4.8V 2,200mha for the ign and a 6V 2200mha Nimh for the radio under the KISS principle. A member of out club went the lipo route and apparently his voltage limiter or BEC or what ever failed. Lost radio control and the whole airplane. A beautiful Tiger Moth. Also I did a stupid thing with only one nut on the throttle arm ball joint. Lost partial throttle control and couldn't idle down for landing. Had to fly around until it ran out of gas. Already had gear down and was able to land ok. Now two nuts and red locktite. Has a 12 oz tank and it is more than enough. 10 oz would be plenty. That would save a little wtg.

raydar,

Thinks for the info on the Graupner 16-8 three blade. Save me money not to try. I have a Grupner 15-8 three blade on a DLE 20 with stock muffler. It turns 8,800 rpm. I may try the "new" MA 16-8 on a 25cc engine I have.

I cleaned up the P-40 a little, filled holes and primed the bottom of the cowl. Painted the aluminum spinner red for 112 sq. scheme. Also added an exhaust diverted because I was getting an oily mess on the belly. Looked scale, like a full size with an oil leak. Have a ATP and 5,000 plus hours so I saw enough of those.

raydar

WOW 8800 rpm on a 15 8 3 graupner, maybe you should try a 16 8 3 then as there is only 400 rpm between these props on my engine.

Thunderbolt47

My Feedback: (8)

Rbean, I ran both engines today with the MA 16x8 props. They both turned 7900rpm and pulled like a horse with both running at the same time. (Sounded petty darn good too) Both engine are new and haven't been broken in yet. So maybe it will gain a few hundred RPMs later.
So does that mean I got two older props?
Kelly

RBean

Maybe or maybe they changed specs again. My "new" prop says 4120T on it. Look at the props and let me know what it says. One of my DLE 20s with a J-tec pitts turns 8,100 to 8,200 rpm with the "old" prop. Tried the "new prop" on two different DLEs and one with the pitts turn it 7,100 rpm and the P-40 here with my home made exhaust turns it 7,300 rpm. You should gain another 100 to 200 rpm with break in so that is real close to what I am getting with the "old" prop. What are they on? Pictures?

RBean

3136, just realized my mistake. You said you wtg is 4.3 kg. I was thinking 4.6. So yours is only 1 kg heavier than mine before the gas conversion. Should work ok with two batteries.