Author Topic: Which Fox .15 for Acromaster? (Read 5018 times)

Bill Adair · « **on:** August 30, 2009, 02:18:51 PM »

I'm considering an Acromaster for my next build, but don't own a suitable size engine.

The engines I'm considering are the Fox, OS, and Enya. Several Fox .15 engines are now on Ebay, at reasonable prices.

Unfortunately, I know nothing about Fox engines, other than the 35 stunt, and 40 ABC R/C, both of which gave me very good service.

Has anyone compared the performance and weight of Fox .15 engines?

Seems there are three basic types, the early steel fin, later slant plug models, and the current high back cover variations.

Any information, and/or recommendations will be greatly appreciated.

Will post this on the other forum as well, so reply to either.

Bill

Robert McHam · « **Reply #1 on:** August 30, 2009, 03:24:45 PM »

For power you can't do better than the Fox with the high back I am told.
Besides most any reasonable 15 should pull it around with enough authority to havwe great fun with.

Robert

De Hill · « **Reply #2 on:** August 30, 2009, 03:37:11 PM »

The slant plug Fox 15x is the preferred engine because it is light. The high back door Fox 15 schneurle will work, but you will have to add lead to the tail to bring the c.g. in limits. The increased weight will affect adversly how the airplane flies. I have only used the .15x in the Acromasters that I have built.

The Flite Streak jr., Ringmaster jr., Magician jr., and the Acromaster were designed for the Fox .15x.

Tom Rounds · « **Reply #3 on:** August 30, 2009, 05:02:10 PM »

The Fox .15X is perfect for the Akromaster. Its like a small Fox.35. Use the same fuel you would use on the .35 (5 nitro, 29% all caster.)
Tom

Bill Heher · « **Reply #4 on:** August 30, 2009, 05:46:48 PM »

I've flown Acromasters with the Fox 15X, OS .10 and .15, and TT .15, I like the 15X, because even with a muffler it needed less lead in the tail to balance, and had plenty of power. It is a fun plane and fits in almost any car.
My Acromaster currently has the Thinder Tiger 15 on it, the Fox is on a Jr Flite Streak (another good flying combo).

I have not put one of my new style Fox .15s on it, but they are a bit heavier and like to rev up more than the 15X. The Fox Schneurle .15 has flown my Ringmaster Jr, and had more than enough power. The RM Jr. with it's thinner wing like to fly a bit faster so they make a good match.

Don't forget to add wing area by keeping the spar / LE / TE stock full length, and a bit of extra length to the aft fuse helps the balance issues.

kenneth cook · « **Reply #5 on:** August 30, 2009, 07:17:38 PM »

Bill, as stated already the Fox is a good choice due to its weight. I'm using a Enya .15 on mine with terrific results. The first Enya I had was the 3303 model. It was great on power but had a bad running away habit. I truly needed to try a uniflow tank but never did. I used a Randy Smith tongue muffler for a FP.40 using the stock Enya strap and it lined up pretty good. It never came loose and it had a good note. I just opened the holes up to 7/64 and didn't add anymore. I worked with the Enya for 2 years until it developed a problem and self destructed. I then went with the 3304 Enya this one seems to be working real well and its currently in the plane. This has no obstructions within the exhaust cut out unlike the 3303 with the casting web in the middle. I believe this was causing problems especially using the stock muffler. I opened the stock muffler waaaaay open as it would just overheat using it. The 3304 has a slightly larger cylinder head with also more fins I suspect for better heat dissapation. My 3303 was a converted r/c version while the 3304 was a c/l engine. The slight changes the manufacturer made turned this engine into a great little engine. I use the Enya #3 plug with castor fuel of no more than 20% oil. I found that after running a higher concentration of castor it would varnish up and it surely didn't like that. I believe this was also due to my engine overheating due to the stock muffler before I drilled it out. The tongue muffler took care of this afterall but I still ran 20%. The plane still likes a little tail weight. This was a bit tricky trying to bury weight in the tail. I ended up with 3/4 oz in the tail for the Enya with the tongue muffler. I do have the coffin backdoor Fox which I want to try. I just think the Enya, OS FP and LA .15's are a great choice. My other Akromaster has a red head McCoy.19 in it and it flies surprisingly well. It took a bit more tail weight to get it to fly correctly. Ken

Bill Adair · « **Reply #6 on:** August 30, 2009, 08:12:01 PM »

Thanks Robert, De, Tom, Bill, and Ken,

The Fox .15X is what I want, and if not for the nostalgia, just because I like them!

Besides, I have almost a gallon of Dukes Fuel, with enough Castor added to bring it up to 28%. My McCoy RH 35 cuts out with that fuel, but it should be OK for breaking in the Fox.

Bill

jim gilmore · « **Reply #7 on:** August 30, 2009, 09:08:34 PM »

You can also move the wing 1/4-3/8 of an inch forward to improve the balance and reduce the amount of tail weight.

Bill Adair · « **Reply #8 on:** August 30, 2009, 09:17:57 PM »

Jim,

The way I build, it should have plenty of tail weight!

Bill

Clayton Berry · « **Reply #9 on:** August 30, 2009, 10:18:01 PM »

All suggestion to this point are wrong. Well intended, but wrong.

Think Cox Olympic .15. Light, purty, and cool. Ultimate instrument for a pretty good plane. Wear earmuffs.

Think cool. Very cool.

Bill Adair · « **Reply #10 on:** August 30, 2009, 10:28:43 PM »

Quote from: Clayton Berry on August 30, 2009, 10:18:01 PM

All suggestion to this point are wrong. Well intended, but wrong.

Think Cox Olympic .15. Light, purty, and cool. Ultimate instrument for a pretty good plane. Wear earmuffs.

Think cool. Very cool.

Clayton,

I would love to have a few Cox Olympic engines to use, but have you seen what they are selling for these days?

All of my Cox engines are .049, or smaller.

Bill

George · « **Reply #11 on:** August 30, 2009, 10:39:20 PM »

Quote from: Bill Adair on August 30, 2009, 08:12:01 PM

...Besides, I have almost a gallon of Dukes Fuel, with enough Castor added to bring it up to 28%. My McCoy RH 35 cuts out with that fuel, but it should be OK for breaking in the Fox.

Bill

Bill,

AFAIK the Fox 35 is the only fox that needs so much lube...because it is a maximum displacement in a minimum case. Duke Fox used to recommend Missile Mist for the 15X. I like ~20-22% lube.

Don't over prop the Fox .15X, it likes an 8x4.

George

Bill Adair · « **Reply #12 on:** August 30, 2009, 10:52:56 PM »

Quote from: George Bain on August 30, 2009, 10:39:20 PM

Bill,

AFAIK the Fox 35 is the only fox that needs so much lube...because it is a maximum displacement in a minimum case. Duke Fox used to recommend Missile Mist for the 15X. I like ~20-22% lube.

Don't over prop the Fox .15X, it likes an 8x4.

George

George,

Thanks again, I'll sure keep that in mind.

Can't hurt to make the initial runs on high Castor, don't you agree?

I can always blend in a little low Castor fuel, to thin it out. Have a new jug of Omega here, that should do the trick.

Just missed a couple of NIB .15X engines on Ebay. Guess I'm going to have to get more realistic, with my price limits.

Bill

Terrence Durrill · « **Reply #13 on:** August 31, 2009, 10:01:23 AM »

Acromaster fans,
I also have an Acromaster powered by a slant plug shiny case Fox .15, but I have yet to fly it. This plane was built with the full span wing and covered with transparent red Monokote. I am expecting it will fly very well. I will be flying on .012 52 foot lines and running 10% nitro/29% castor fuel with a Master Airscrew 8/4 propeller. It has a 2 ounce Perfect metal fuel tank, which should be plenty to go 5 minutes of flight. I am glad to hear you guys who have actually had your Acromaster/Fox .15 in the air and have had good results. I can't wait to get my plane in the air

.....Terrence Durrill

Clayton Berry · « **Reply #14 on:** September 04, 2009, 02:11:35 AM »

Quote from: Bill Adair on August 30, 2009, 10:28:43 PM

Clayton,

I would love to have a few Cox Olympic engines to use, but have you seen what they are selling for these days?

All of my Cox engines are .049, or smaller.

Bill

Make me an offer. I have one that has never been run. No packaging, but wrenches and maybe a few heads. Beautiful engine.
apexclayton@hotmail.com

Dennis Moritz · « **Reply #15 on:** September 04, 2009, 02:54:04 AM »

You should be able to pick up an LA15 cheap, used, also. They're screamers. Often a choice in RC combat. FP venturis and needlevalves can still be purchased from tower. Making LA15 CL conversions easy enough. Powering the Akromaster depends on what you want. A .10 or .09 is enough to fly one of these. The smaller engine is probably a better choice for flying sport stunt. If you want jollies and an instinctive smile response power up with an FP15. Funny, laughing out loud, fast.

Ward Van Duzer · « **Reply #16 on:** September 04, 2009, 01:29:03 PM »

I flew one of these years ago and it was a BLAST! I did find the 15X to be a little "snarley" though. Read finger eating! Miske told me to ad a head gasket or two. Made a big differance!

Enjoy!

W.

Robert McHam · « **Reply #17 on:** September 04, 2009, 03:39:34 PM »

Quote from: Clayton Berry on August 30, 2009, 10:18:01 PM

All suggestion to this point are wrong. Well intended, but wrong.

Think Cox Olympic .15. Light, purty, and cool. Ultimate instrument for a pretty good plane. Wear earmuffs.

Think cool. Very cool.

The more I think about this the more I want to try on of the Cox .15 engines. The Olympic would be way cool but I could live with a medallion or Tee Dee if I had to.
i used to have a thing about getting one of the Conquest 15s but have pretty much talked myself out of ever having one of them.

Robert

john e. holliday · « **Reply #18 on:** September 05, 2009, 08:25:54 AM »

Will try again as this computor is so screwed up. I myself would go with a newer engine. The price of the glow heads for the Cox engines is out of this world. MECOA does make a conversion head, but, I have not tried mine yet. Have fun, DOC Holliday

Robert McHam · « **Reply #19 on:** September 05, 2009, 06:04:39 PM »

Doc, speaking only for myself, I would trust a Mecoa adaptor for a 15 long before I would for the smaller 049-061 engines.
Besides, I believe they need to be flown not set on a shelf to collect dust... What a sad life such engines face.

Seems that the Cox 09 and 15 engines see less flying time than other engines of this size. I cannot name one person that flies a Cox 09 or 15 on a regular basis. Seems a real shame.

Robert

john e. holliday · « **Reply #20 on:** September 06, 2009, 07:20:37 AM »

My daughters Acromaster with the Cox Medallion .15 is still flying. Just need to get her out on it more often. DOC Holliday

Robert McHam · « **Reply #21 on:** September 06, 2009, 10:48:11 AM »

Quote from: john e. holliday on September 06, 2009, 07:20:37 AM

My daughters Acromaster with the Cox Medallion .15 is still flying. Just need to get her out on it more often. DOC Holliday

So is it a great combo?

Robert

Bill Adair · « **Reply #22 on:** September 06, 2009, 11:02:13 AM »

Well, now I'm having second thoughts about engine choices.

OS engines has a promotion going, and is offering a $10 merchandise certificate with the purchase of a .15 LA engine. Requires a trade in of any engine, regardless of condition, make, or displacement.

That makes the .15 LA only $54.95 out the door of my LHS (no sales tax), and it comes with a 3 year warrantee! I also get rid of one of my junk engines.

Haven't found a new Fox .15X (or any other engine) that comes close to that deal!

Guys in my club are using the .15 LA in the Acromaster, and are very happy with that combo.

Thanks for your advice everyone, very much appreciated.

Bill

john e. holliday · « **Reply #23 on:** September 06, 2009, 11:37:24 AM »

Bill, sounds like a good choice.

Robert, it does what the daughter wants it to. She does standard wingover and some loops. DOC Holliday