airraptor

My Feedback: (66)

bone stock 11x8 13,100

Ernie Misner

That seems pretty darn good. I wonder how much stronger it is than the 55AX. (and how much heavier)

Thanks,

Ernie

airraptor

My Feedback: (66)

The 55 is 18.5 ounces with muffler
The 65 is 22.7 ounces on my scale at home. The muffler adds alot. it alone is 5.3. I did take the fins off the muffler, weld it together and removed the baffle and long muffler screw. it is now at 3.9 ounces. the engine alone is 17.5 ounces for a total of 21.4. This is very close to the 55. if i remember correctly the 55 turns the 11x8 at 12,000 or less it is to much for it.

The 75 is very close to 25 ounces so its not a viable 55 replacement.

If you every were going to buy the 75 should just get the 95AX since is .4 ounces lighter than the 75.

Ernie Misner

Good job of lightening up that 65's muffler. A black mac's muffler at about 2 ounces might be a good way to go.

Thanks for the interesting info, .... oh, and I have been taking a look at the Evo 60 just for kicks also.

Ernie

airraptor

My Feedback: (66)

yeah but if went with the macs muffler i would lose power over the stock muffler.

A 12x7 mounted in the plane the engine turned just a tic over 12,000. Not as strong as hoped but it does what i wanted with this plane.

CustomPC

It's interesting that the bore and stroke for the .65AX is almost square so i would expect this engine to be less of a revver and more for torque.

OS list the practical rpm as 12,000 for the .65AX.

The old .61FX is over square with a larger bore than stroke and OS list the practical rpm as 17,000rpm for that engine.

The claimed power figures for both engines favours the .61FX by about 10%

I'd love to see some comparisons between the two with the larger prop sizes.

Ernie Misner

Are you thinking the mac's pipe would hurt the top end? I fly aerobatics and 3D and would not care about the top end so much..... the weight loss might be worth it. What do you think? On the OS 55AX.

thanks,

Ernie Misner

Hobbsy

My Feedback: (102)

Ernie, if you could find it there was .60 sized engine shootout a few years ago in one of the magazines and LA .65 bested some pretty good engines, in that particular shoot out the Fox .60 bested them all which is not a surprise with the Fox .60 being one of the best kept secrets in this hobby.

Ernie Misner

Thanks Hobbsy, great to be talking to you. I looked at the Fox 60 on their website and am a bit puzzled..... could not seem to find any specs such as weight whatsoever. Perhaps I missed something?

http://www.foxmanufacturing.com/inde...ac8ea53016843c

Thanks loads,

Ernie Misner

Hobbsy

My Feedback: (102)

Ernie, here the weights of a Fox Eagle 4 .74, a Fox Eagle 4 .60 and a LA .65, al are wearing their stock mufflers, prop washers and prop nuts. The Fox .74 is the lightest due to its thinner sleeve. I pulled the Davis Diesel heads off of all three and mounted the stock heads to make the weights stock weights.

airraptor

My Feedback: (66)

Hobbsy how does the fox compair to the 65's above rpm numbers?

On your scale what are 1:06.2 stand for? kilograms or what?

Hobbsy

My Feedback: (102)

The Fox .74 weight is 1 pound 6.2oz, the Fox .74 turns a Graupner 12x8 at 11,200 and the .60 at 11,000 even on 5% nitro with 20% castor lube. As a Diesel conversion the .74 turns a Graupner 12x8 three blade at 9,650. The respective weights in oz would be,
Fox .72===22.2 oz
Fox .60===22.7 os
LA .65====24.8 oz.

Ernie Misner

That's good homework Hobbsy, thanks. You really went the extra mile and it is interesting. The Fox 74 would be the way to go then, and amazing that it is lighter than the OS 65 which is bushed. Or do the Foxes not have ball bearings?

Thanks again,

Ernie

Hobbsy

My Feedback: (102)

Fox makes a couple of bushing engines, a .40 and .45, the .46 through .74 are all ball bearinged. The .46 is the only ABC engine they make now although they may have a a few .74 ABC sleeves left. They ran out of .60 ABC sleeves a few years ago except for some .60 ABC sleeves wtih pipe timing. I keep hoping they will stroke the .74 into a 1.00, it would easily match up to others 1.25s and 1.50s.

landeck

My Feedback: (1)

Ernie, I have a new Fox Eagle IV .74 on my Escapade 61. It is a great engine giving solid, reliable performance.

Bruce

SpeedBoy

APC prop ???

airraptor

My Feedback: (66)

Yes speed boy APC prop. I have a large range of props all APC and i never use them for flying just as a bench mark prop. I was only able to get 12,900 with it mounted in the plane. air pressure and hard vs softer mount contributed to lower number.

SpeedBoy

Good !!!! then I think nothing bad for this engine.

the Wasp

My Feedback: (1)

more info here,, my 61 FX with a Slimline Pitts burning Magnum 15% Nitro spins an APC 11x8 at 12,200 (got it written down)

Jim

KLXMASTER14

15,000: 11/7 APC prop, 15% Byron fuel w/ 2 oz extra castor oil (break-in mix), Mac's 10cc quiet pipe. Mounted in a Classic Pattern Aircraft.

Needless to say, hauls *****.

MetallicaJunkie

how much did you cut off the header to tune it to 15k?

airraptor

My Feedback: (66)

with that pipe although a decent number it isnt in the engines best power range. The 55AX on the Jet muffler is close to 14,000 on that prop. The AX bone stock like to be in the 12-13,000 range on the ground.

I did try a 10x10 APC on the 65 and i cant remember the rpm but i think it was over 14,000. that flight my plane went in and my thoughts were on the little tiny pieces left from the plane. soon as i switched the 10x10 i had some flutter issues. i found the problem and it was on the control hook ups on the servo side inside the fus. well i soldered up the nyrods and. let cool off well it set over night to cool and i forgot to put the servo screw in the servo. I was doing some full power dive test as i do in all my planes. the flutter was gone and after the 4th dive i lost the elevator. i wasnt pulling out till the 30-40 foot mark. well no elevator. I went to idle. i even tried to roll some and use the rudder but at 130+ and only 40 feet no chance. it hit so hard the wing left full length 1" indetations in the ground. the carb broke clean off and so did the muffler. it even broke the top of the glow plug off lol. I only had one servo that was intact but the wires were pulled off. the fuuel tank was turned inside out and the LiFe battery was flattned into a ball no fire though.


the 65 is a great engine for someone looking for a bit more than the 55 with only couple of ounces more.

AllTheGoodNamesAreTaken

My Feedback: (180)

Numbers are peak using 15% Cool Power, OS 8 plug.
Stock muffler:
11x7 - 13,000
11x8 - 12,400

Macs long header cut to 4.5" and 1060 muffled pipe (there was no gain in RPM from 4.75 to 4.5"):
11x7 - 14,800
11x8 - 14,000

Sport_Pilot

For some reason there is more information on the CL version.

http://www.foxmanufacturing.com/inde...ac8ea53016843c

Because the CL people often do not use muffler pressure, and thus they need more fuel draw, the venturi is often smaller than the RC carb and so the RC version often performs better thant the CL version. Also Fox tends to underrate them somewhat because they will replace the engine if it does not perform to their published performance. As I recall the RC version does 13,800 on an 11-6, and on 5% fuel at that.