flybyjohn

My Feedback: (2)

I know I will get two correct answers to this question but am looking for the best performance for my situation. I have a hanger 9 corsair 60 size from about 5-6 years ago, maybe longer. I had originally put a os 91fx 2-stroke on it and taxied it around in the street but have never flown it. I then mounted the 91 fx in a big stick 60 to make sure it was reliable and consistent. I have since acquired a os 91 surpass I 4 stroke that seems to run pretty good. Now for the million dollar question. Which engine should I put in the corsair? I am looking for something that will pull the corsair around with authority with good reliability as my first priority. The sound is NOT on the top of my list. My only concern with the 4 stoke is that it may be a little lacking on power being that this is a 60 size bird, and a 91 4 stoke is about the power of the 61 size 2 stroke. A little extra power is always nice to get you out of trouble in some cases.
So what do the masses say?

flybyjohn

My Feedback: (2)

After going though and weighing the pros and cons of all the suggestion, I have decided to go with the 91 4 stroke. No actually with all kidding asside, I have seen a lot of these cosairs flying with 91 four strokes, some have had larger engines but alot had the 91 4 stroke. I set the 4 stroke on the engine mounts last night and it fit perfectly. I will only have to drill one hole to set the throttle linkage and the muffler might make it out of the original hole for the fx. A small opening will need to be made for the top of the head but that is right were the glow plug hole is for the FX.

daveopam

My Feedback: (9)

The one I fly for a friend is powered by a Saito 1.00. It is plenty of power IMHO. Your OS 91 should be a little stronger but maybe slightly heavier. Will be a great combp.


david

A6TEXAN

i have a Magnum 1.20 4 stroke in mine. with a 16 oz. tank. i run a 14x 8 prop. plenty of speed. also you will probably want to re-enforce the stabilizers on this aircraft. also if you need some help on improving the stock retracts let me know. i have a few good tips.

flybyjohn

My Feedback: (2)

I rotated the engine from 7:30 to the 9:00 position, just because the carb was way below the tank and when inverted would be way above it. With it in this position, the carb is about 1/3 up from the bottom of the tank. I had to add a piece of 1/8 ply to the nose becuase of the cut outs in the second layer of firewall. The blind nuts needed another layer when I rotated the mount. A 120 is a lot more power than my 91 so now I am second guessing myself, however as daveopam said and from the videos I have seen a 91 seemed to pull it around decent. A6TEXAN, I am always looking for good advise on improving things. What I have done so far on these retracts are to put heavier duty ball cups on the rotation links. That was something I read about right after I bought it. This is one of the original arfs that needed all of the beefing up. I have also made aluminum struts on my lathe to bolt to the original retracts. I had put a little bit of fiberglass on the inside walls and firewall but looking at it now, after it sitting for years, I did not do such a good job.

daveopam

My Feedback: (9)

Time to get it going John, your flying season up there is what,,,, 7 weeks? :-)

Be sure and let us know how it flyes when you are done.


david

Avaiojet

I'm using a 120 4S in mine.

I would suggest you use the 4S.

Great model BTW.

Charles

flybyjohn

My Feedback: (2)

I fly almost 11 months of the year here. There is snow and it is cold but airplanes still fly. Sometimes monocoat gets so cold that if you thump it with your finger it will shatter. There are some big lakes here that are good to fly off of. But you are right, the good flying season is moving fast. I am waiting on a more powerful retract servo now, my hitech hs75 was not strong enough to lift the gear without stalling on 4.8v, 6.0v will just get it done so I want to get some more torque for safety sake. I suppose I could retract during a roll to get the gear up, going down is not a problem.

A6TEXAN

hey John, you may want to consider doing the retract servo mod of installing a seperate servo for each retract. its an easy mod. the servos go in the outer wing panel adjacent to the retract. the torque rod is only about 2 inches long for each retract mechanism. its in this thread somewhere. i looked for it but i couldnt find it. i have a part number for some good ball caps if you need it. sounds like you may already have them though. if you cant find the servo mod in this thread, let me know. ill cut open the monokote on my wing and take some pics of the install for you.
http://www.rcuniverse.com/forum/fb.asp?m=9888491

flybyjohn

My Feedback: (2)

A6TEXAN, thanks for the tip on the dual retract servos, I did see something talking about it at one point but already have mine all set up and working well, just don't have enough power to pull them up. All I have to do is screw the new 260 oz-in servo in place of the 91 oz-in servo that is in there now. If I have problems with them later I will probably change them to the dual servos. What ever you do, don't cut your covering for me but I do really appreciate the offer.

fly24-7

You may want to consider going with electric retracts. I have a set of E-flite 85 deg. 60-120 sized retracts in a 46 sized P-51. They're beefy enough for the 60 sized. $150 and no servos to screw with.