goshawk911

Let me know how you get on with the conversion. I would test fly it with a 24/10 2 as I know that's a good combo. I have tried Xoar and Beila. The 24x10 is a xoar.
You may find that with the CDI conversion you get more RPM and hit the sweet spot with the semi-scale prop you have. I know that some have have the Saito 84R engine have been using the 22/10
but i reckon they are probably achieving much higher rpm than we are.
Let me know how you get on. I am sure you will love it as its the best War Bird I have flown.

chorner

I know with the Xoar 24x10 on this engine with CDI, achieving ~5700-5900 RPM on the ground is doable. Which probably is a bit under-propped at this point for the 7-77. I would assume the sweet spot should be around ~5,400 rpm which should unload a bit in the air. The engine manual states the max rpm to be 6,300 so probably best not to push it too much past that.

I think with the 3 blade props you need at minimum a 12 pitch, but more likely something like a 22x14 or 23x14 from what I'm reading/understanding lately? I think there's enough thrust with a 3 blade 22 or 23" diameter, just not enough speed with the efficiency loss of 3 blades to get this bird flying fast enough? ... all speculation at this point, but I've tried to find more information myself without having actually flown it yet.

goshawk911

A 22x14 may be worth a try. Hadn't thought of going that high on the pitch. I may try and get hold of one and see what I get

Zeeb

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Man you guys are having propeller day dreams IMHO, talking about those size propellers on that engine. The preferred prop for the FG84-3R is the Biela semi scale 22x12 3 blade and you guys are talking about more prop on a smaller engine? Let me maybe save you some money and grief; the two gentlemen who put my Corsair together with the big Saito also each have one of these Corsairs powered by the glow radial and after a bunch of testing, they fly theirs with a 24x10 Mejzlik 2 blade..

Here's the FG84 on my Corsair with the 22x12 Biela 3 blade prop.

njmheli

Hi.

I have had my 7-77 on the test stand for about 6 months now ( still finishing off the Corsair ),I have it converted to CDi from Adrian at CH.
I managed to purchase a "Tacho" that plugs directly into the ignition box that Adrian supplies..........so pretty accurate on the RPM reading.
The 7-77 is well run in now and and is running on the "mix" as suggested by Evo,at the moment it is 10% Nitro,I am running a Biela 22" x 12 x 3 Blade,the latest on the ground readings I have at Max throttle ( still a little rich on the needle ) is 5100rpm.......................using the 22" x 10 x 3 is far too near the un-load estimate of MAX rpm advised.

So in theory,I would expect the rpm max in flight to be around 5600 +...............

I agree that the two blade option would be a safer bet for all round performance.

Regards..................Nick (UK).

chorner

Zeeb, the engine can handle the prop sizes listed here without a doubt. Don't forget, just because your 84CC engine is larger, it also runs on Petrol. You're not getting as much power per CC as with an equivalent engine running a methanol/nitro mix. It's been estimated that you lose somewhere around 30% of your performance between gas, and nitro.

I know the Evo has 7 cylinders, which versus the 3 on the FG84 loses a bit of efficiency, but these two engines both running on CDI have pretty similar performance characteristics with a bit of a higher RPM advantage on the top end to the FG84.

Do a bit of research etc. before you slam what you don't know

chorner

Nick, too bad you haven't flown it yet! Would love a report on that 22x12 Biela since I too will be running on CDI. Still don't want to give up on the 3 blade combo yet, but I presume a 2 blade 24x12 is probably the best combination.

Zeeb

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I didn't slam anything, I made a suggestion based on past experience and what I know about engines and airplanes. I'm a licensed A&P Mechanic and hold a Commercial Pilot's license in addition to working not only on race cars but Reno racers with Dago Red being the one I used to work on every year for about 4 years.

Lastly, research may be fine but it da*n sure doesn't replace actual experience. How 'bout this one for research; which propeller is more efficient? If research provides all the answers, why are you guys trying different propellers?

Shall I go on??? I think not.

chorner

Zeeb, I suppose as a part of the Pilot's and A&P license you chose and select propellors for the aircraft you fly? Clearly there are two guys here with the 7-77 that show these propellors I've suggested actually work, and can be spun above 5,000 RPM on the 7-77. Did you miss that part...?

Not all propellors are going to perform the same when it comes to model airplanes especially. One companies "22x10" might be different than another. This isn't BS, it's a fact. Also, the window for a range of propellors that fly the aircraft is wide enough that between different pitches, diameters, blade counts and brands, there's enough there to try (and yes, trial and error is part of even an Engineer's job... I'm an engineer in a different field) that no one propellor can be stated as perfect.

How about this corsair running a 24x12 on a non-CDI Evolution 7-77? https://www.youtube.com/watch?v=soVeVLmWYRI .... seems to fly and run just fine to me.

njmheli

Hi Guys.

Well,this is getting a bit interesting !!!!!

I think it is a question of what suits you is worth a go,lets not forget,that there is a wealth of information on this particular "thread" about this Corsair / engine combo,each to his own !!! Plenty of info on this subject at the near begining of this thread by the HH guys.

I agree with the comment about each manufacturers differences in performance of blade types and blade / pitch combos,"Maxim" in this thread flies his Corsair using the Siedal 77,but with I think a Xoar 22 x 10 3 BL,but his bird is about 9lbs lighter !!! and he says it gets to scary above 1/2 throttle.............unloading ???

We all know that the petrol engines will be able to swing bigger props / pitch set ups,due to the torque available,but are not as powerfull per cc as Nitro engines as said,hence the 84 has more cc that it's nitro brother FA450.

The 7-77,glow or CDi has more internal losses than the 84............simple mechanics denotes this !!!!

I'm sure that in much earlier posting by one of the HH pilots,saying.......anything around 5200 rpm on the ground will be ok for this Corsair...?

I think that we should all just enjoy this thread and experimentation is a great way to pass on great info for all to read and try !!!! What is good for one guy,may not be good for another............just depends where you are in the World flying these great birds..........high elevation or low elevation,all set ups will differ in their outcomes.

Lets not measure each others d***s,but pass on results to each other for the good...........

This is Affas and his CDi Evo 7-77.........2 BL www.youtube.com/watch?v=EM4McMUgTk8

Anyway............keep up the builds and info,hope to get mine finished off in a few weeks.

Kind regards to all......................Nick (UK).

chorner

I agree, njmheli ... for what it's worth as well, in the description of the video posted by Affas that you linked to he says "Initial propeller was a 24x10 but the engine is strong and we will try a larger propeller with higher pitch."

Peter_OZ

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paper aeroplane anybody?

cublover

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more in a second

cublover

My Feedback: (47)

Hey Dave,,,,,,,,,,,,,,Good to see someone from Horizon here to ask questions...so mine is.... What do you see in the future for a giant scale hanger-9 p-38... and if you DON't see it,,,why??... Seems for years,,guys like myself who just love the Hanger-9 series,,,would love to have this plane...I can see it now...2 boxes,,,with ALL the trimmings!! Silver covering with markings, pilot, gear, everything minus engines,,,for about 1600$... tell me some good news!!!!

cublover

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PS..120" would be AWESOME!!!

goshawk911

Well Said njmheli

Like I said in my earler post I went with 24x10 2 as it gave the best performance for me. I check the RPM every time I fly it. Air Temp has an effect on overal performance and I find I can get a range
any where between 5100 and 5500 rpm.
I have attached a couple of pics of mine flying last spring.

34th B-1Bcc

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John, How about a large scale or even a 40-60 size F2G Super Corsair. Do both race 74 and 57 or Miss Port Columbus. Also love to see a P-51A , P-51B or more yet one nobody seems to know the P-51H just to be more different. Can you give us hints on a possible Skip Stewart Prometheus P2 coming out now that Horizon sponsors him? Thanks for your hard work on the current line up! They are all winners for me! Love to see a Big Pitts S-1 or Pitts S-2C!! hint hint Thanks again

David Eichstedt

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Thanks for the input, guys. We appreciate it!

Unfortunately we can't really comment on future releases. Too much risk involved for a few different reasons.

flypilot

That is me flying Affas corsair last summer and the prop we found to give the best performance on the Corsair was this 23x13 2blade
: http://www.hobbyking.com/hobbyking/s...idProduct=9055

This prop gave the machine good pull and a great top speed with just the right amount of power...

There will be a video of this airplane with that prop coming out hopefully soon when Mr. RCscaleAirplanes at youtube gets the video done.

H

chorner

Did anyone have to trim the trailing edge of the gear door bays to get the gear to retract without making contact with the fibreglass there? I trimmed the right side as close as possible without letting light seep through under the gear doors and the wheel has proper clearance when retracting now... but the left side I'd have to trim a good few millimetres past the trailing edge of the gear doors to have it retract without contact.

I noticed the Robart (electric) gear I purchased, that the right trunion is a few mm shorter than the left... but it still concerns me I had to dremel the trailing edge lip on the gear bay to begin with. Seems to me that should be a little better fit right from the start.

jonyfever

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chorner i had the same problem i to trimed a small section but then later found that the bottom part of the scicor has a screw loosen this and push on the gear to hold it in place. then u should be able to adjust the strut by moving the collor closer to the wheel hard to explain in words but you can get it to sit up a little more than now im sure may take a few tries good luck .

goshawk911

I had this issue to. I adjusted mine on the scissor part of the retract, this worked for me.

clover creek

I did this also. My only concern is,getting the track of the wheels correct!

see you soon,
John

drottman300

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I have the zp62 on mine and had to add almost 5lbs of nose weight!

chorner

Ah, figures! Got it all adjusted now, just have to be careful to make sure you keep the alignment (toe in/out) set properly but that did it. Have to compress the strut a bit, then tighten up the bolt. Hope I didn't over tighten it now as the clamping part just about touches on the tip of it by the bolt head now oh well, nice and secure anyways. Hopefully that doesn't loosen and slide around at some point!