How do I finish this project??

[akeyzoo]

Folks,
Let me preface by saying that I have been flying electrics for a few years, and would have never considered jumping to the slimey side. But here is the story, a friend of a friend was into GLOW and unfortunately passed away. The family kept his complete planes for decoration, but I have the rest. I am looking to build a kit that he had that was unopened in the box.

It is this P26 pea shooter from here:

http://www.giantscaleplanes.com/P26_71.htm

He also had the following (approximate engines):
A used .48 4S
A New .91 2S
a new huge super tigre 325
a used .68ish 4S, i dont exactly recall. The carb didn't move on this, perhaps I need to tinker.... Interestingly this motor is below the size recommendation, but is the actual motor in the pictures in the instruction manual for the plane!

Anyways,
I would like to build this plane, using a motor above. It seems to me the .91 2S would be the best choice, although it is bigger than the recommended motor. Will this be a problem? I would love to do 4S, but mine seem undersized.

What servos should I use? I am used to micro servos for my electrics. Don't want to break the bank. Are Hitec HS-322HD's any good for this application?

Is the Hitec Supreme SS 7C a good reciever? Seemed cheap, dual conversion, and phase selectable.

Hate to sound like a noob, but I am to glow!

BTW, my largest electric is a converted Magik glow plane. is nice for size, but with my power setup isn't a barnburner.


Thanks for your help. Next I will have to search for a primer on how to actually run/tune thes motors as well as break them in. Any advice would be great!

Chris

[ivanc]

Looks like you do not have the right engine. This is a pretty heavy plane for a .60 2-stroke engine. I wonder if by 60-2c they mean 60cc 2-stroke gasoline engine but this looks too much of an engine for the plane. And then the 91-120-4c confuses me even more. Usually planes of this size and weight use 26 to 50cc gasoline engines. So I'm lost here. Someone else might have an idea about it.
HS-322HD servos wouldn't do the job. You need high torque servos for this plane preferably digital ones.
The Hitec Supreme is good for the plane. You can use it with ANY PPM FM radio as it can be switched to positive or negative shift.

[akeyzoo]

ivanc,
What is the problem with using the larger 2S engine like the .91? Doesn't seem significantly heavier. BTW, I am used to WAY overpowering my electric models with brushless and LiPos...

Chris

[ivanc]

.91 means .91 cubic inches which is 15 cubic centimeters (cc). 60cc is 3.66cu.in. So if the plane is designed for 60cc and you instal a .91cu.in. engine you will be significantly underpowering the plane. To me the plane in question looks too big and heavy for a .60cu.in. engine - more likely a 26-36cc gasoline engine will be OK for it. It doesn't have much wing area (736sq.in.) and it's pretty heavy (approx. 9lb.) so you'll end up with high wing loading - 28 oz./sq.ft. which should be compensated with speed so you'll need a more powerful/bigger displacement engine.
But again I'm not familiar with the plane, so hopefully someone with more experience will chime in and provide more helpful info.

[akeyzoo]

Ah, so perhaps that super Tiger 325 is the right motor then, it is 1.989 Cu In, or 32.61 cc? It is a bit of a beast.

Chris.

[fhhuber506771]

The key to determing the engine size.. it says flying weight of 8 lbs som oz with a 3 cyl Saito.. That is appropriate weight for a heavy .60 ci 2-stroke glow model.

You can get away with a .60 2-stroke glow. You would be happier with a .75 to .91... maybe even a 1.00 appx.

You could get by on as low as a .65 4-stroke....the .68 4-stroke would fly it a bit sluggishly but it would work. Probably scale performance which no one really seems to want to deal with. You would be happier with a .91 4-stroke minimum.. 1.20 is not excessively out of line if you want torque rolls.

Also.. its size is comparable to my Goldberg Tiger 60... the weight is just marginally higher... I'm using a .91 4-stroke and have a bit excessive power for use as a trainer, but its what it needs for pulling off the AMA Sportsman Pattern. The Tiger 60 has far less drag than that big round nose would give you so.. I would not put any less on it.

My conclusion... from the engine selection you HAVE::

Use the .91 2-stroke and be a little careful with the throttle. Especially on the first take-off VERY SLOW throttle advance... use a full 300 to 400 ft runway!

Don't "torque turn" it and cartwheel down the runway due to excessively fast throttle advance. (and that .91 2-s will do it to you in a heartbeat)

**********

BTW... If it was in my "hanger" It would get my .91 4-stroke and I'd put smoke in it.. flying weight would go up to about 9.5 lbs.. 10.25 with full tanks and I'd be on cloud 9 flying it that way.

[Dead Beat]

ok i have to say something here . i looked at the spec's for this airplane and the 60 2 stroke will fly it just fine!!! a 91 fourstroke would be just fine 28 oz. wing loading it not bad for a plane this size i flew a kraft superfly for years with a KB 61 in it and it flew good at 10 pounds. the P26 is not a 3D airplane!!!!! my extra flew ok with a ST 3000 in it at 17 pounds it was under powered but flew pretty good. if put a big ole motor on it your asking for all kinds of trouble. the biggest motor i would put on it would be 120 fourstoke with that motor or 91 2 stroke this plane would be a bullet!!!!!!! one ? what altitude to plan on flying at ???

[Viper Pilot]

I agree with Dead Beat. A 0.61 2-stroke would be just fine for an 8-pound Peashooter.

Viper

[akeyzoo]

OK, i have another issue. I have done a few searches, and apparently this plane is not exactly a great flyer. Hmmm. From what I have seen the landing gear are AT the CG, which is a problem in erms of landing, she wants to tip over. Hmmm.

DeadBeat/Viper Pilot. A 0.61 2S may be gerat for this plane, but I do not have one :-) I have a .91 and bigger. Would the .91 just rip this thing apart? Hell, I can always set an endpoint on throttle below max!

My altitude is a few hundred above sea level, maybe 800.

Oh, and what servos (inexpensive) should I go with?

Thanks all,
Chris!

[fhhuber506771]

You have a left stick.. just don't run full throttle in level flight. (and full throttle dive is WAY out)

At some speed, the model will have flutter. if you exceed that speed the wings rip off. Youcan solve that problem 2 ways.

1) throttle management (people need to learn that full throttle is not the only way to fly)

2) Propeller choice. If you go with a long low pitch propeller you can choose one that gives a calculated "Pitch speed" (pitch times rpm at full throttle) which is less than the flutter speed. THEN even full throttle in a dive would have reduced chance of fluttering the model apart.

As prop diameter increases in relation to wingspan (more prop disc size compared to the model's drag really... but this is an OK comparison for the models). Actual measured top speed can EXCEED calculated pitch speed (partly the engine unloads and rpm increases... partly the prop airflil gives a bit more than the calculated forward thrust than just what the pitch says)

A side bennefit to the long low pitch is.. you get better vertical performance. A steeper climb from take-off is safe because you won't drop airspeed as much.

2 side problems are... more torque and less ground clearance.

If using the .91.. I'd put the longest prop on that is appropriate for the engine and cleared the ground with the tail up such that the airplane's wing was in appx 5 deg negative AOA angle. (that would give a passable margin for a rock on the runway)

And.. as I said.. the .91 is the only engine in your list of available nes I think would adequately power it. (without being so much that you couldn't go above 1/3 throttle ever)

**********

Servos.. I started with Futaba 3004's in the Tiger 60.. they are adequate. I switched the aileron servos to 3001's which have about the same torque... but are more "crisp" in response... much better servos. the rudder i swapped to a "Traxis" (RC car) steering servo rated at 90 in-os to cure the first surface to flutter's flutter. (I needed to have the extra airspeed flying the airplane in Sportsman Pattern contests. I also beefed up the hinges and reinforced the fin attachment.)

I used the 3004's except on rudder in a 10 lb Fokker Dr1 with the .91 4-stroke (and needed the Traxis servo on rudder at all speeds)

Keep your speed in line with the model's design... and 3004's will work. If you go fast.. you need stronger servos and may need to strengthen and stiffen some things.

[akeyzoo]

fhhuber506771,
Awesome advice, thanks. I'll keep you posted!

[Dead Beat]

fhhuber gave you some great advise !!! the longer prop and lower pitch will give more verticle
lower speed and more of a constant speed. in a dive the big prop will act as a big dive break! the only reason i said something about this plane plane. in one of your post you said maybe the ST325 was the right engine

good luck Jim

[akeyzoo]

HEY! Update!!! Woohoo!!!

I was digging through some more boxes and found..... drumroll please.....

An OS .91 4S engine. (FS-91 Surpass) Used. It has some slop in the carb linkage, but I think I can fix that!

Also, I bought 5 futaba 3004's.

Anyone have a site they could point me to that details setting up an engine test bench, and how to tune this engine? Should I do any other maintenance on the engine? I peeked in the exhaust and it has some carbon on the exhaust valve. Also, I haven't yet found the exhaust yet, so i will need to keep looking.

Chris

[fhhuber506771]

I have a Surpass-II .91... but you can get the manual from the www.osengines.com website.

I have never bothered making a test stand.. I bolt the engine on an airplane.. tie the tail to a post and do my engine break-in/testing on the model. It works.. and costs essentialy nothing (6 ft of strong clothesline or something like that)

The muffler for the .91 is about $27 if you find a new old stock original for the Surpass (first version) its a stronger metal then the Surpass-II muffler and I recommend it even though its more restrictive to the exhaust. (the Surpass-II muffler will fit... I use an older model muffler on my newer model engine though... )

You will also need a header pipe which is a short slightly bent stainless steel tube that has been threaded an unusual metric thread. (no die that I can find...) Its $0.50 worth of metal for the wonderful price of.... $25. But.. nothing you can do about it.

don't run it without the pipe and muffler... you can burn the exhaust valve out that way. It needs the restriction.

The .91 4-stroke is a much better engine for the airplane.. and I'd start with a 14X6 prop if you have the clearance. 13-6 or 13-8 is the next choice. The engine will turn 10,00+ rpm... but don't try it. around 8,300 is a happy rpm for my engine. You can much more easilly over-lean a 4-stroke than a 2-stroke because they will keep running when you are giving them less than half the fuel they need. (for cooling and lubrication..)

[Mendnwngs]

I believe the websites terminology is 60-2c as in .60 Cu In, 2 Cycle

That weight is flyable with a .60. A 90 4 stroke would probabaly make it happier tho :)

-Jason

[akeyzoo]

I emailed OS and recieved the manual in under an hour in .pdf form. Excellent. I will need to dig through all of the stuff I have to see if the muffler isn't in there. I am looking for two pieces it appears, the threaded header pipe and the small cylindrical exhaust I suppose. I will also refer to my new found instructions for adjustment purposes.

The reason I would like to run this puppy on a test stand is that it isn't new, and the motor mount instructions for the plane are different for 2s and 4s, if this motor doesn't run well I may use the 2s motor.

I will need to go to my lhs and see what fuel options are available.

Chris.

[Dead Beat]

there will also be 2 thin nuts! there lock nut's for the head and muffler i have had a 91 surpass for about 15 year's great engine. the engine need's back pressure to run right i found that a 14/6 master airscrew K works best but dont know if they make them anymore

Jim

[fhhuber506771]

The thin lock-nuts come with the header pipe. (I know... because I had to order a replacement... messed one up trying to tap it for smoke)

Cheapie test stand... cut a rectangle out of a hunk of 1/2 inch srap plywood that fits the engine... screw it on. use C-clamps to hold that to a table. (or screw it down if you don't mnd screw holes in the table... or use a sawhorse... whatever...) a chunk of 1X2 gets nailed onto the ply behind the engine and a nylon wheel strap is used to squeeze a bit of pressure on a pushrod hooked to the throttle. 2 to 4 cup hooks are used to rubber-band anchor the fuel tank.

Should be able to do the whole thing for the cost of some cup hooks and scrap wood from a local construction project dumpster. (even make a sawhorse from the scrap...)

[akeyzoo]

Cool, thanks. I will try to pick up some fuel and see what goes. The manual describes adjustments pretty well, and I have a tach.

I found an 8 channel reciever (NIB) made by "DAD". Anyone heard of them? Only issue I see is that it doesn't have a user-replaceable crystal. My hope is that I find the Futaba 9Z that I found the instruction manual to, has to be somewhere....

Chris

[fhhuber506771]

Yes, I remember the DAD line. they were good. However... it might be the old wide-band type... and I don't know if you can even look up if its narrow band.

The Futaba 9Z is an outstanding radio... but be sure to check the NiCds (maybe have someone cycle test them if you don't have a cycler that will do it..) No sense losing an airplane over a bad battery.

[akeyzoo]

uh oh, I cant find the exhaust pieces anywhere. Interestingly enough, I found the exhaust manifold and muffler to a 1.2 4S, but of course it is too big. Bumm deal. I will need to find a retailer for these. Is there a superior aftermarket product?

[fhhuber506771]

There are some upgrade exhausts that should fit... produced intended for "Pattern" flyers using YS or Saito engines... Not cheap... http://www.centralhobbies.com/Exhaust/index.htm

I would look at www.towerhobbies.com and find the exhaust parts that are stock for the .91 FS-II....I just peeked... and the header price is down... but the muffler price is up.. comes out about $60
********
OOps.. they now include the header with the muffler... cheaper yet.. its $40 (by the time you get shipping

[akeyzoo]

I see this:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCC19&P=Z

for 59 bucks.

[ivanc]

Here're the muffler body for the FS-90 Surpass: http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=OSMG6776&FVPROFIL=++&search3=Go and the pipe assy.: http://www2.towerhobbies.com/cgi-bin/WTI0001P?&I=LXCA99&P=V - each for $24.99 for a total of $49.98.

[ivanc]

And here's the whole assy.: http://www2.towerhobbies.com/cgi-bin/wti0095p?FVSEARCH=OSMG2858&FVPROFIL=++&search3=Go for only $36.99.

[akeyzoo]

You da man. You are like my airplane concierge. Bought a new glow plug as well.