Engine For CMP Spit
 

Hey guys, i was wondering if a O.S 140RX FI engine would be to heavy for my CMP Spitfire, The O.S 140RX FI weighs in at 810 grams.

Nic

RE: Engine For CMP Spit
 

What's the Specs on the Spit ?

RE: Engine For CMP Spit
 

Should be enough. Got a Saito 150 in the CMP FW190 and it's just perfect. Not much better than scale really.
Same with my CMP Spitfire. GT25cc Brillelli. No unlimited vertical or insane power. Just a very solid scale feel without adding a brick to the nose for balance.

RE: Engine For CMP Spit
 

Its a .90 size spit, 1800mm wingspan.

What weight are those motors you have kurt??

Nic

RE: Engine For CMP Spit
 

Here's some specs direct from Horizon Nic.

Saito 1.50S

Type: 4-stroke
Displacement: 1.50 cu in (25.00 cc)
Bore: 1.33 in (34.00 mm)
Stroke: 1.08 in (27.60 mm)
Cylinders: Single - Chrome Plated
Engine (Only) Weight: 30 oz
Crankshaft Threads: M8 x 1.25mm
Benchmark Prop: 16x8 APC @ 8,800
Prop Range: 16x8 - 18x6
RPM Range: 2,000 - 10,500
Fuel: 10%-30% Synthetic
Mounting Dimensions: 138 x 69 x 134 mm
Muffler Type: Cast
HP: 2.5
Cylinder Type: AAC
Carb Type: Barrel, 2 Needle Valve
Crank Type: Bal Bearing



My 25cc Brillelli weighs around 3 lbs with muffler and electronic ignition. I didn't hack the cowl up as it looks. It's been the host of several engines including an OS91FX, SuperTigre G2300 and a OS160FX. The big 2stroke heads sticking out the side made for a huge velocity stack opening. LOL
I have another cowl for the Spit but just haven't gotten around to messing with it. It runs great and stays cool the way it is. These lower priced warbirds will never be Top Gun winners anyway.

Here's one of several threads on the plane.
[link=http://www.rcuniverse.com/forum/m_2865431/mpage_1/key_CMP%2CSpitfire/tm.htm]CMP/GSP Spitfire[/link]

RE: Engine For CMP Spit
 

Thanks for those specs Kurt, how did yours fly with the O.S 160 in it?

Just bough a O.S 160FX FI today :) should be good i hope.

Nic.

RE: Engine For CMP Spit
 

Had a supercharged YS 91FZ four stroke in mine, and it was a rocket: [link=http://www.warbirdobsession.com/cmp_spitfire/videos/show_pass.wmv]Show Pass @ Full Throttle[/link]

No butchering up the cowl:

RE: Engine For CMP Spit
 

The 160 is way too much engine for this plane IMHO. Folks fly 1/4 scale acrobatic planes with that engine. Plus the fact that they can be funky when inverted. Especially when your tank is mounted so high like it will have to be. The FI version may not be as bad,, I've never had one of those so I'm not 100% sure. Mine flew fine with the OS91FX but needed a full pound of weight at the nose.
My days of warbirds and two stroke engines are over. The sound of a big 4 stroke will convence you of that.
Scott Ellingson from Brillelli Engines is going to make my carb, stack and muffler extentions narrower on some future projects which will keep me from butchering anymore cowlings. I'd never do that to a true kit build scale warbird. But as many have pointed out,,, the CMP Spit lacks quite a bit from being very scale. It's a short,fat looking Spitfire compared to the real deal. But if you CG it right it can be one of your best flying knock around birds in the hanger.
If you want to keep the scale look with a clean engine mount as Richard did ,, go with a 4-stroke. The YS engines come ready to go with a pressurized fuel system so the tank height doesn't matter. On my Saito's mounted inverted I use the Cline demand regulator and check valve . This keeps the fuel from flooding the engine between runs and draws from the tank only when the carb needs the fuel. The pressure is obtained from the muffler on the 4-strokes and from the crankcase on the 2-strokes.

Hope this helps. There are several tips and mods for these CMP planes here in the WBs forum you should look over. The planes may be lower priced than others,, but you are going to spend more hours fabricating , beefing up everything (especially the firewall) and basically making straight what was mis-aligned from the factory. My last CMP (the FW190) didn't have a single control surface or wing mount area that was flush or the same diameter. I had to sand and resheet both ailerons and flap surfaces just to get a flush fit. Plus the wing was way too big for the saddle. If your Spit is like my old GSP 72" Spitfire then you'll at least get a decent fabric type covering. Mine's lasted for years now after painting and clear coating.

One last tip on this plane. Program your elevator rates so you'll have at least one setting with the bare minimum throws.
Just a dab will do it . Very , very touchy.

RE: Engine For CMP Spit
 

Hey Guys, thanks for your advice, yeah i sorta know the 160 is an over kill but i have a few other projects in mind for the future that it will suit so it didnt really worry me. Hopefully with the fuel tank height and pressure it shouldnt be an issue, if what you read about the FI is true, its supposed to monitor RMP and temperature of the engine and the fuel flow and keep the right air/fuel mix no matter what the attitude, altitude and engine speed. But i guess i will only know if thats all as good as it sounds after i try it.

I can get a pitts compact muffler for it, dunno it it is gonna fit in the cowl or not, i will have to do some measuring.

Nic

RE: Engine For CMP Spit
 

I have been doing a bit of reading on the os 160 and see lots of people have perry pumps for them, do i need one of these or not??

Nic

RE: Engine For CMP Spit
 

My OS 160 ran great on the ground without a single hint of problem. However, once in the air, the engine died about five minutes later due to insufficient fuel flow to the carb. The pressure from the Pitts muffler wasn't enough so I would say it's a good idea to invest in a Perry pump.

RE: Engine For CMP Spit
 

Ok thanks richard. I just asked Bill Bax what to do, he suggested i dont need a pump or the muffler pressure for the FI version, so i guess it gets pressure from the crankcase??.

Nic

RE: Engine For CMP Spit
 

Ok,, you got the FI pumped version. Makes a big differance. Although,, I've heard even those can act just as Richard discribed.
It's not much fun deadsticking a warbird over and over.
Check with the RCU two-stroke crew and ask them if you'll need a check valve to keep from flooding. I used a Perry pump and all it did was make the flooding worse until I put a check valve between the carb and tank.

RE: Engine For CMP Spit
 

ok i will, but y should i need a check valve if the air/fuel mix is ment to be constant and controlled the whole time, if it needs a check valve dosnt this mean the ECU is not doing its job?? or not?

It would wanna be better than a standard 160FX cos it was nearly double the Price.

Nic

RE: Engine For CMP Spit
 

Should i use the standard fuel tank that comes with the kit??
and the standard engine mounts?? or should i get a O.S radial mount for my 1.60??

Nic

RE: Engine For CMP Spit
 

The 160 can produce some serious vibes. It's pumping out close to 4 HP. If your going to use it I'd go with the best engine mount you can get. Again,, .... if your going to mount it inverted ,,, and you'll have to so there will be some cowling left to look at. You may run into some trouble with starting and reliability issues. The OS160 may be a good choice for some warbirds. But you'll be using the Pitts muffler on a sleek fighter like the Spit I would think. Stock muff is HUGE. And from experience I can tell you that all will seem great until you've been flying for a few minutes and it dies suddenly and for no reason. Then your driving a 12 to 13 LB warbird without any prop wash under the wings.

Besides the 2 stroke forum you might do a search in the Pattern Forum. The 160 was used quite a bit by these guys for contests before they mostly switched to the YS 4 strokes. And I believe they mounted them mainly inverted as well because of the narrow cowlings on the Pattern Ships. 4 Strokes don't seem to mind being inverted as much as a rule.

Last thing,,, and I hope Richard and others will add to this and back me up. The OS160 topic is a giant mixed bag of fans and enemies here in RCU. My advice is read everything you can about them and make your decision based on specs and veteran RC'rs advice.

RE: Engine For CMP Spit
 

I might as well jump in. I'm on my second cmp spit. Lost the first when I flew thru the sun and was blinded. The second is setup the same as my first one. Saito 1.20 for power. Seems a good match to me.
Edwin

RE: Engine For CMP Spit
 

Yep, the OS160 topic is huge. About 50% have had success with the engine (the standard non FI version). The other 50% failed. One of my buddies at the field has one with many deadsticks before he figured out the Perry pump. Mine stopped in midair after a couple of laps. Hopefully the FI version will not be as troublesome.

RE: Engine For CMP Spit
 

Thanks for your input guys, every bit helps :D What retracts have you guys been using??

Nic

RE: Engine For CMP Spit
 

I use spring-air retracts. Dont recal the model number but I use the 3/16 strut wire fastened to a 1/2" oleo. Works pretty good. I think it is 104HD series.
Edwin

RE: Engine For CMP Spit
 

SpringAir here too except I use the 3/8" Robart struts to conserve a little weight since using the gas engine.

RE: Engine For CMP Spit
 

jez boys, isn't a 1.60fx Fi some what over kill for that little aeroplane. I don't mean power vise, it'll be so over powered you'll be needin' 45deg of right thust to hold a straight line... I'm talking about the sophistication and the price. That engine is a classy piece of kit, even used at the top end of the F3A circuit... why put it in a 2 dollar, sunday fold away Spit when any old banger would do... preferably a decent cheapo 4 stroke.

PS Chaps... the coment regarding the illusive inverted 2 stroke problem. People on the pattern scene have been, and still are, running many different kinds of 2 strokes inverted without any hint of a problem, certainly not becuase of the inverted position. It seems that the problems exclusively occures when they're opperated by folks out of that scene... go figure.

You need a nice chineese, SC 1.20 four stroke. Cheap, reliable and cheap. Perfect motor.

RE: Engine For CMP Spit
 

Yes my OS 160fx flies my Platt 80" 18.5 pound Zero with much authority. 1/2 to 3/4 throttle is plenty.

Carl

RE: Engine For CMP Spit
 

Richard,

Did you have to add any weight to your CMP Spit with the YS 91?

-Ed

RE: Engine For CMP Spit
 

I had to add an ounce of lead to the stock plastic engine mount. Had I used an aluminum mount, then I wouldn't have to add any.