I'm finishing a Sterling/Brodak Yak 9...

[Brian Browning]

Projected weight looks to be 21-22 ounces.  Power will be an Enya .29 (model 5224).  Is this a heavy vibrator or fairly smooth running powerplant?  Would I be better served using an O.S. .25?  Bought the Enya on Ebay, and it seems to be in very good shape; I just haven't had the time to put it on my engine stand and play with it.  I'll try to post some pics of the plane when it's finished.

[Phil Spillman]

I have a Yak-9 about to be finished and am planning on using either an LA .25 or an FP .20 with tube mufflers on either engine once flying. I have flown both the P-51's and Ringmasters on these engines and have found them to be most adequate power plants. The Enya engines were fine for me as well back in the late 60's and 70's but the power potential of modern engines is superior for my vote. The FP .25 is yet another possibility. All of these modern engines work well and consistently so on 9 X 4 and 9 X 5 props. I have seen others use 10 X 4 props but I have not tried these as yet.

[Brett Buck]

I have a Yak-9 about to be finished and am planning on using either an LA .25 or an FP .20 with tube mufflers on either engine once flying. I have flown both the P-51's and Ringmasters on these engines and have found them to be most adequate power plants. The Enya engines were fine for me as well back in the late 60's and 70's but the power potential of modern engines is superior for my vote. The FP .25 is yet another possibility. All of these modern engines work well and consistently so on 9 X 4 and 9 X 5 props. I have seen others use 10 X 4 props but I have not tried these as yet.

    The 25FP is generally a lot more stable on 9-4s than on 10-4s. You need more RPM to get the same speed, and more rpm means more fuel draw. With a 10-4 on the 25 it usually needs some sort of restriction on the venturi, like an air filter, a few layers of pantyhose, or an ST needle. The 20 works with the stock venturis even on larger props.

      Brett

[Robert Mathison]

This is a photo of my Yak 9 hope to fly it this weekend.
      Bob

[Brian Browning]

Bob, that sure is a beauty!  Hope it flies as well as it looks.  I made a few modifications on mine.  I added dihedral, wing-mounted the landing gear, and added adjustable leadouts.  I'm going with the black and green camo.

Thanks for the engine/prop combinations.  My .25 is the LA version.  Now that I think about it, I also have a NIB K&B Sportster .20 r/c.  I've heard these little guys can swing a pretty big prop at low rpms.  Any thoughts on replacing the carb with a venturi and needle valve?  As you may have guessed, I'm a sport flier, with a soft spot (or soft head ) for odd-ball engines.

[john e. holliday]

Robert, the Yak looks a lot better than the one I had years ago.  Mine had McCoy 35 for power and moveable flaps.  It should be a great flying plane.  DOC Holliday

[Bill Little]

Hi Brian,

I am going against the popular opinion here and saying to use the Enya 29.  It is not a real bad vibrator, and has plenty of power to fly the Yak!  I would just set it in a rich two stroke and let her go.  A 10-4 to 10-5 prop depending on how fast you like to sport fly.  I have mine set up for a Veco 19BB and hope to get it finished soon.

As to the LA 25, it would be a good one, also.  The FP 20-25 engines are great, but you have two engines there that will work fine, already, for your purposes.  Great thing about Enyas is that they are almost impossible to wear out unless they are really abused!

Mongo

[Bill Morell]

One sure fire way to wear out that Enya is to not use all castor lube in your fuel.

[Joejust]

Here is my Yak as built for the CLW article on using this plane for two events, racing and OTS. The stunt version uses the LA.25, FP .25 or .20. For racing the landing gear,tank and engine remove for instalation of a single LG and a Fox .35

[Don Curry AMA 267060]

Brian: I had Scott Riese make a venturi for a K&B sportster .28 for me and it worked out very nice. I have run 10/4 apc props on it and believe it will handle a 10/5 which I intend to try.

Don

[john e. holliday]

To Bill M.  any engine will wear out fast if ran flat out all the time.  I have engines that have been run on blended fuel ever since the synthetics have com on market. 

Joe J, make that three events.  Add Old TIme Stunt to your agenda.  Throttle back during maneuvers. 

Have fun,  DOC Holliday

[Bill Morell]

To Bill M.  any engine will wear out fast if ran flat out all the time.  I have engines that have been run on blended fuel ever since the synthetics have com on market. 

Joe J, make that three events.  Add Old TIme Stunt to your agenda.  Throttle back during maneuvers. 

Have fun,  DOC Holliday

Doc, I don't recall saying anything about being run "flat out".  How you can make a statement like that regarding my post is beyond me. Ask anyone who runs  the older Enya's and you'll most likely find that almost all of us run 100% castor.

[Joejust]

Joe J, make that three events.  Add Old TIme Stunt to your agenda.  Throttle back during maneuvers. 

Have fun,  DOC Holliday
[/quote]

Hey Doc, re-read my reply. The Yak-9 is set up for OTS already. Here is a picture of the same plane set up with a Fox.35 with single LG for sport racing. As you can see, hanging from OTS to racing is simply a matter of changing the LG rom 2 wheels to one, using a "Don's" wheel. the tank also is easily changed from a stunt tank to a racing tank. this is a real fun versital ship. Hopefully it will enter its first race in October in Salem,OR. Check out the article in the last CLW. This article is a companion piece to the Brodak P-51 conversion to Profile carrier.

[john e. holliday]

My mistake as I can't read.  I thought this was the one you did for carrier also.  DOC Holliday