I just picked up the Sig CAP 231 ARF... looks great. What engine should I put in this plane? I want to learn to fly tighter IMAC like aerobatics (not 3D)...

1. Webra speed 120
2. Webra Bully (35CC on glow)
3. Webra Bully (35CC on gas)
4. Saito 180
5. Moki 1.35
6. Super Tigre 2500

The Bully on gas, then glow then the saito seem to be the most heaviest, in that order... The Moki is pretty spunky, but I am not sure how it stacks up to the webra 120 or Super Tigre... I need some help here ;-)

thx in adavce.
Tim

Hi,

The MDS 1.48 is an awesome engine.

It is turning a Menz 17x8 at 9000 rpm.

20* C, 10% nitro and a Bisson muffler with the crimped ends cut off.

Cutting off the crimped ends gained 500 rpm!

I am using the recommended H-9 4 stroke super plug p/n HAN3011

Unlimited vertical on my 13 lb airplane.

Throttle response and midrange is excellent.

It is easy to tune, and in 4 or 5 gallons of fuel it has yet to quit!

Starts easily with 1 or 2 backward flips.

I have a Perry VP-30 pump on it.

The engine probably does not need a pump, however I put pumps on all my airplanes for a more consistent engine run from the start of the flight to the end. My choice!

Inexpensive too!

John Jeffries

Cool... but what engine should I use from the above list?

HELP ;-)

Tim

Hi Tim,

I think you need a ST 3000!

Of the ones you listed I would use the Saito 1.80. My second choice would be the Moki or the ST 2500.

When are you going to stop messing around at Marymoor and start flying with us at Cascade? If you want to get into IMAC Cascade is the place to go. There are several very good and helpful IMAC guys that love to help us IMAC newbies get started.

Here is my new IMAC plane... Guess I'd better get busy practicing that sequence...

All are excellent engines!
The MDS weighs 3/4 lb less than the big Supertigres or the Moki 1.80 engines.
The Saito 1.80 needs 30% fuel for serious power.
The Webra 1.20 is good but not the power of the MDS 1.48 or the Moki 1.35.
I would pick the MDS 1.48 or the Moki 1.35 or the OS 1.60 or the Supertigre G2300.
I own all of the above engines except for the Moki 1.35.
Good Luck!
John

Wow... the MDS sounds really good. I have heard other really nice comments about GMS retooling...


Well, Galen says go with the Saito 180... it has more tourqe. Why wouldn't the Moki 1.35 do the trick here? It spins a 16X10 APC at 8700 RPM and runs on cheap FAI...

I need to settle on the engine ;-) any comments or opinions???
Tim

If you must go with something from the list....saito. If not, definitely an OS160fx.

OS160fx: this is the engine for IMAC hu? OK. I can buy one. My reading has put the MOKI 1.35 over this engine, but not specfically for IMAC.

Do you just like the 1.60 or do a lot of IMAC guy use it for it's consistancy?

what do ya think?

PS>>>

what prop should I be looking at.... big prop, Small pitch? Smaller prop, larger pitch?


thx!!!

The 160 is my personal favorite. Thats about it. It starts easy, every time, and it will swing a 18x8 pro-zinger. I have even heard of it swinging a 20x6 mejzlik (spelling?). If you like speed, it will also swing a 16x10. I did add a Kline fuel regulator to mine but that was just to keep the carb setting steady throughout the flight.

It also uses very little fuel compared with other engines....don't know why though??>> It pulls my sig extra 300 straight up (not out of a hover though) and it weighs in at 13lbs 2oz. All the Sig caps I have seen weigh 12lbs or less, so you should have plenty of thrust.


just my 2 cents.

Saito 1.80 all the way. I have seen this motor fly this plane with super authority off of 15% nitro. Were talking snap rolls stopping in knife edge flight while doing rolling circles. Good vert. and I think would be a great IMAC set up for basic or sportsman (If its big enough I cant remember). I think its the best aerobatic bird sig has come out with and it out performs the 300 they have by a noticable difference. Though you can put a gasser on it and sig reccommends the FPE gasser I would go glow all the way b/c the wing loading will get on the high side with a gasser.

180 it is... Thank you, guys!
Tim

There goes Galen pushing his ST 3000 again. Dude - give us a break already!

I have been flying this plane with a small gasser (McCullough 33 cc). Not enough. Just purchased a 35CC MVVS. Check out the specs. The guy at Morrishoobies.com knew all about this plane (he has one) and says this is a great match.
I hear these engines are amazing. 20 lbs of thrust!!
Love the plane. Built like a tank.
http://morrishobbies.com/product_inf...roducts_id=452

Also flew it with a Saito 180. Flew great. I just am tired of the glow scene so am trying the gassers. Nothing wrong with the Saito 180.

I have the Sig Cap with a Supertigre 2300 and Conley Mega carb and Bisson Pitts. Plenty of power and very reliable. The ST engines can be a problem - carburation. I'd use the OS 1.60 for similar or more power and you don't have to worry about the carb. Keep the plane light. I made a new dihedral brace from good aircraft ply (stock piece is crap), I glassed the wing center section, and I put bass wood rails in the wing for solid servo mounts. The stock servo mounts with the potato chip covers results in aileron flutter. I used coreless 42 oz-in servos for the ailerons and Rocket City hardware and there is no flutter.

Choice of engines is not bad. Have seen the Moki 1.35 in use in a 72" giles 202, flew great, lots of power. I have a Sig Cap but I have a Moki 1.8, Bisson muffler, 5% nitro, extra oil. Presently using a 20 x 8 Moki Prop at approx 6,500rpm. Unlimited vertical at 12lbs, 6oz.

I have the Moki 1.35 in a Lanier 1/4 scale Edge. It is plenty of engine: unlimited vetical and low weight. It takes a while to break it in, but then it has at least as much power as an OS 160 and uses less fuel. I run mine on 5% and use an 18 x 8 prop. The big prop keeps it from spinning too high and provides very noticeable braking. You have listed some great engines, but you will not be disappointed in the Moki. It also has significantly less vibration than the Saito 180, which has very high vibration in my opinion, resulting in airframe wear and loss of anything not kept in place with loctite.

I have a Sig Cap 231 ( my third one ) and love the aircaft . Sorry I can't comment on the engines you listed . I have a YS 120FZ with pitts style muffler <---this all fits inside cowl . Be careful with the servos you choose I lost my first cap to flutter caused by stripped gears in Futaba 9201 servo and don't use ca hinges . I now have Hitec 615HS metal gear servos and recommend them strongly.

FBaity:
Did you flutter the aileron servos?
Were they installed according to Sig's directions mounted on those lite-ply covers provided in the kit?

I'll guess the answers are yes. Sig's method for servo mounting is the cause of the flutter, not your choice of servos. I'm using 42 oz-in Futaba servos mounted on bass wood rails - no flutter.