Hi guys

I have an OS FT300 that has been in my collection for some years now and I would like to know if any of you can recommend me putting it into a Great Planes Christian Eagle ARF 68.5" wingspan (28.7% scale).

If any one of you actually have or have had this combination, please let me have your comments - good or bad.

Thanks for the input.

Cheers

Springbok Flyer

I have been flying the exact setup you mention for the last two years. The OS 300 twin is a great match for the GP Eagle.
I also have a homemade smoke system added that really spices up the flights. If I remember correctly, all up weight is 20 lbs. Including smoke system and onboard glow. ( I'm using a 4000mah NiCad for onboard glow). Running a 20 x 8 Zinger prop. I don't believe you can go wrong with this setup. I am using Futaba 3010 servos on everything except throttle.
Trust me. You will like it.

Shepp

Shepp, just out of curiosity what does the OS turn a 20 - 8 prop ? I have a Saito 270 and am considering an OS 300. My 270 turns a MA Classic 20 - 10 @ 6500 safely. Apples to oranges I know but it will give me some idea if the OS is much stronger than my 270.

Several years ago, I build the GP Pitts for a customer and installed the OS 300 Super Gemini Twin in it. Slimline made a Pitts muffler for it (not listed on their website or in their catalog, but available for special order) that had the exhaust tubes come out of the cowl at the scale location and gave the 300 a wonderful sound. I used an onboard glow system and the only holes in the cowl were for the mounting screws.

You will love the way the GP Christen Eagle flies and the sound with the OS 300 twin.

Shepp and Jake (and Don),

Thank you, exactly what I wanted to hear.

Shepp, did you have to cut the cowl in any way to accommodate the FT300? I'm asking as I am not keen on doing that to fit the engine.

Don, my two cents worth - I have flown an Extra 300 (scrath built) and a Christian Eagle (Pilot Kit) with the Saito 270 (single carbie) and used a 20 x 8 Top Flite prop. It produced as you say around 6500 rpm. Always felt the Christian Eagle neede a bit more grunt - however, that was at 5500' altitude??? From what I've seen the OS FT300 seem to have what I'm looking for and the GP ARF should be a touch lighter too. I also run the 320 Pegasus and the 300 Sirius (both with 20 x 10 K Series Master airscrews and get around the same rpm (at sea level). I like the heavier prop and was going to go the same route with the GP Christian.

Cheers mate(s)

Springbok Flyer

Answering the question about cowl cut-outs, "None" The exhaust turn on the left cyl. is close to the cowl but does not touch. I did install a remote needle valve. I used a OS BGX remote needle mounted at the bottow of the cowl . I did not remove the existing needle assembly, just opened it about 4 or 5 turns and then adjust with the remote. This system was recommended by Baxter at Tower. and works like a charm and I don't have to get so close to that prop. The only problem I have is at the beginning of the day, drawing fuel up to the carb. I just place a piece of fuel tubing on on the vent line and blow until I see fuel dripping at the carb. From then on, no problem all day.

Answering the question on rpm with the 300 and 20 x 8 prop. If I remember correctly, I am turning right at 7000 rpm.

My muffler system is home made. I used a couple of pieces of 1" alluminum rod and bored them out to a wall thickness of about 1/16" then turned plugs to fit. I drilled the plugs a little smaller than the id of the exhaust stubs and fastened the canisters to the exhaust stubs with double setscrews. Exiting from the canisters, I bent stainless steel tubing to exit the cowl in the scale location. Joined the canisters to the stainless tubing with sicilone tubing. I have had no problems.

Oh yes, Between the bend of the exhaust stubs and where the canisters go, I wrapped 1/16 copper tubing
( airconditioning capilliary tubing) about 3 turns as tight as I could get. then drilled the canisters for a pressure tap . Hooked the copper tubing to the pressure tap with black fuel line and begin pumping in the smoke oil. I get tons of smoke out of both exhaust. To really make this work good, overwrap the copper tubing with 1" fiberglass tape, two or three turns and make an aluminum flashing cover to keep everything in place. This holds the heat in and keeps the airflow from cooling the preheater.
The smoke system can be built in nearly the amount of time it took me to write this, so is not a big project. But I believe a preheater system for the four strokes is a requirement for good smoke.

Sorry about the long post, but I keep remembering things. :^)

Shepp

A lot of good info here for us that are interested in these engines. I've come to the conclusion ( I think ) that I will not gain much by going from my 270 to the 300. I guess I'll have to spend my money elsewhere

Don M.,
Since you're not planning on using it, I will give you $100.00 shipped for your OS 300...

If I had one I would certainly sell it to you for $100.00 - NOT. But what I was saying was that I have a Saito 270 but considering upgrading to a 300. But after reading the rpm figures on the OS 300 my 270 is very close. I get 6500 on a 20 - 10 and it seems that the OS 300 is getting around 7000 on a 20 - 8. Not exact conparisions but close enough for horseshoes and grenades.

If I see one for a $100.00 I let you know

Don M.

I know what you are saying and understand.

If you do find one for $100.00, please make sure that it is NIB!!!



Jake

PS,
The guy that I built the Pitts for has never flown it. He had me put about 8 flights on it and it flew great. I am now considering buying it from him. It is a shame to let is set and not get flown. The last time that it was in the air is over two years ago.

The only problem you might encounter is the length of the motor. The 270 is a good bit longer than the 300 OS. I have both and I was going to put the 270 on my GP Pitts but it was going to require moving the firewall back whereas the OS was just the right length so I installed it. I have a Menz 22x8 prop on my 300 twin (don't remember the rpm) and it pulls the Pitts around rather well. Mine weighs 17lbs wet. Maybe the Eagle can deal with the longer motor - good luck.

Cobra 1,

I have built both the GP Pitts & Christen Eagle for two customers and thought that the firewalls and cowls were pretty much the same. The Pitts got the OS 300 and the Christen Eagle a Fugii 50.

If you look closely at the photos I posted ealier on this thread, you will notice that I added three 1/4" plates to the front of the original firewall of the Pitts in order to get the recommended 6 1/2" spacing from the firewall to the engine thrust washer using the OS 300. This measurement is the same on the Pitts & Christen Eagle. Are you sure that the OS 300 was mounted without any spacing? Can you post photos?

Thanks,
Jake

I have the GP Christen Eagle and love it. If you haven't already, please research the strut failure problem. Sucks to lose a nice plane over a stupid mechanical failure. I was lucky!

Hi mate

Thanks for the warning - please can you give me some direction for the required research?

Cheers

Springbok Flyer

rcjake, I see your pictures and I can only say that I did mount it directly to the firewall and the cowl fit perfectly as well. Here are a couple of pics. I can't remember (senior moment) but I might have mounted it that way so tail weight was not needed. It is a heavy motor. By the way, the Saito is 27mm longer than the OS. (148mm vs. 175mm) A little over an inch.

Hi all from Australia,

I too am now the very excited owner of the CE from Great Planes. I'm putting in a 3w-55-cs and swinging a 22x8 (a little less pitchy as I'd rather a strong climb out than overall speed).

My questions is about servo's on the elevator and the rudder. I know there is just one on each in the instructions, but I'm a little dubious as although this is only a 29%, it is bipe and therefore has a large surface wing area and is, naturally, heavier than a mono-wing of the same size.

So for the rudder, I'm going to gang-up 2xJR_DS_8711's in the middle of the fuse as far forward as I can fit the two. And will use a standard 'pull-pull' wire. The elevator's, I'll have 1x8711 on each mounted on either side down the back.

I know this probably sounds like overkill, but it my F3A days the stronger, quicker servo's just add a more 'crisp' control, never lagging or departing from your intended line of flight.

I would love to hear what other people have done and what servo's they've used.

all the best

Jamie

My friend test flew his CE today had a supertigre 3250 flew great once the motor is run in more it will rule the sky why spend big dollars as a ST 3250 can do the job. Barry

Anything of that size will "do the job" but compared to a 4 - stroke twin the sound of the ST would be so aggravating I would never fly it.

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My guess is that the 300 would show a greater power increase over the 270 if the prop load was increased a bit. Maybe not...

I just bought a NIB OS 300 Twin. It sure is pretty. My other multi-cylinder engines are Saito and Magnum (1.60). I'm new to multi cylinder engines in model use. I'm like a kid at Christmas. <G>


Ed Cregger

I'm watching an OS 300 on e - bay right now - you never know I have a 1/3 Space Walker kit and the OS heads would look so much better than my Saito.