Shark 15

Three questions:

1) If you built a light Shark 15, what engine would you power use?
(modern or vintage)

2) Would you use the movable flaps, or not?

3) 3" Bellcrank and 1" horns??

Thanks!
Bill <><

K&B Greenhead Torp .15 or a Max .15 Steelfin if you can find a decent sample. As to the flaps, you can put them on if you like, but it probably isn't worth the bother in this case.

Also good choices are the Fox Steelfin or early monoblock slant plug 15, and the Enya 15 in the 60s or 70s. If you are a Cox fan, try one of the milder .15s (Cox made a bunch of different .15s). Some will say even a Medallion .09, or a Tee Dee, anyway.

ABC Schneurle modern engine wise, just about any of your favorite Asian Rim .10s will do.

And here's a wild one...a Norvel .074. They claim .38 HP @ 22K!? I've got the motor, but haven't tried it on anything yet.

OS baffle .15 from the era of the Max S 35. Very light and runs 4-2-4 well. Not a lot of power, but should power a light airplane. Since flaps don't help the .35 size, my guess is that they are even less help on the .15 size airplane, plus they would add some weight.
Steve

My error on the flap question. I read "Shark 15", and visualized a small profile and somehow got to "Magician 15" which does not need the movable flaps. I guess I can charge this to a Senior Moment.
Steve

>And here's a wild one...a Norvel .074. They claim .38 HP @ 22K!? I've got the motor, but haven't tried it on anything yet.
>
>Currell

I put the venturi assembly from a BigMig .061 in mine but haven't run it yet. I don't do COLD.

>2) Would you use the movable flaps, or not?
>

Yes, absolutely. They are on the big ship, and for a reason. Build it light and set the CG correctly and they will be a big boost. We have 1/2 A ships with flaps. Yes they work.

Jim Thomerson had one that flew extremely well powered by a TD.09. Of course, Jim had a lot to do with the flight performance!

30+ years ago, I did one with a Webra .09 diesel - flew pretty well with an 8-5 TF wood prop.

Some years later, a friend made a Shark 15 with a full fuselage (which I now have). He used a Rivers Silver Streak .15 diesel, and the only way to tame it was with a 10-3½ TF! Capable of 9+ minutes on a 2 oz tank!

Thanks for the responses so far.

How about #3?? Does anyone have an opinion on going to a 3" bellcrank and bigger horns? Wouild there be a benefit?

Bill <><

Hi Bill. The three inch bellcrank was put in the kit at the last minute because it was felt it would slow down the flaps and elevator response, which was too quick on the original. Yes, go with the 3 inch crank and 1 inch horns. As to an engine, OS.15? Er, uh, Fox .25!!

Hi Ty,
Hadn't even noticed that the bellcrank is a 3" one in the kit!!! LOL!!
BTW: How do you know I have a kit?? Which one??
As to the Fox 25..... nah.... I have the Bluebird for that, and when I get a Lil' T-Bird built, one goes in there, too.
I'm just gonna build all the planes I wanted as a kid, but didn't get! LOL!!!!!!
Bill <><

Hi Bill
while discussing with Ty how my trip to KOI went I must have I mentioned it to him that you got a kit of the shark while there

hope that wasn't a whoops?

Hi Walter,
Nah..... that wasn't a problem! Ty and I just have to bust each other's chops every now and then. Ask him why he owes me dinner now. Not Mickey D's either!! LOL!!
Got some projects ahead of the Shark, but I want suggestions now so that I will be set when I can get to it. What I did look at in the kit looks great!!
Thanks!
Bill <><

>Hi Walter,
>Nah..... that wasn't a problem! Ty and I just have to bust
>each other's chops every now and then. Ask him why he owes
>me dinner now. Not Mickey D's either!! LOL!!
>Got some projects ahead of the Shark, but I want suggestions
>now so that I will be set when I can get to it. What I did
>look at in the kit looks great!!
>Thanks!
>Bill <><
>
>Just an Old Advanced flyer.

thanks for the kudos on the kit

when you get Ty to take you to dinner get him to take you for
Eye-Tal-E-Yen ....LOL !

I'll take you out for dinner at my favorite French restaurant-Le Jaque in le boxx. Ha.

Ty,
Now, Buddy, y'all ain't gettin' off THAT easy! LOL!!
(Fox 25, remember?? ROTFLMBO!!)
Bill <><

I shall never forget and it's still written in my engine log. I know of a great steak house or and Italian Ristorante we can go to. Highly recommended by my travel agent, Mary. They won't let Walt in there any more. Ha.

>I shall never forget and it's still written in my engine
>log. I know of a great steak house or and Italian
>Ristorante we can go to. Highly recommended by my travel
>agent, Mary. They won't let Walt in there any more. Ha.

WHAT they're still mad about the dancing on the table thing? LOL !

Bill,

I haven't seen anyone mention the OS LA15. It is a great little motor right out of the box. I have one on a "Fancherized Acromaster". The only mod I made was to remove the restricter section of the muffler. (It doesn't have a cone, but an approximately 3/4" section that restricts down to about 1/4") Oh yes, I cut the "stinger" off the muffler and opended it up to 1/4". The plane comes in at 21 oz and flys as good a pattern as I can fly.

Also, Circle Burner has two on a "twin clown". Really interesting plane.

As for your Shark 15. What are the dimensions? If it is a big plane like it's big brother, then you would have to build it really light. If it is going to come in "heavy", you might try to find an FP 20.

Hi Bill!
I think it is a 36" WS, it is one of Walter's kits, and Jetco put the kit out in the '60s. Then it was recommended for .09 to .19.
Hence the "15" designation. Walt's kit should build pretty light, and a modern "10" would probably be enough. BUT, enough is never "ENOUGH"! LOL!! I am thinking a fairly light engine for balance purposes. I haven't seem a LA 15 fly, but I think it would definitely be enough power, but is it light enough, and how much fuel would it need for the pattern?
Thanks,
Bill <><

Bill,

The LA 15 comes in at 4.6 oz without the muffler. I fly it with a zinger 8 x 4. I set the rpm by ear, so I can't tell you what rpm to launch.

Oh yes, I've been using an old perfect tank modified to uniflow. I believe it is 2 oz. It measures 3" long by 1" high and is sort of a rounded wedge design. I have only been flying it this winter, so I don't have a lot of experience with it. I believe for a proper pattern, I would put about 1-3/4 oz to full tank.

Bill

OK,

As one with experience, I've watched long enough. I have built and flown two examples of the Jetco Shark .15 from kits as well as one scratch built version from the Jetco plans. All three flew very well with the same set up--Fox .15 slant plug, TF 8×6, .012"×52' lines, operating flaps--although the one I built from scratch with somewhat lighter wood than that in the kits flew better that the ones built from kits. It was this model that convinced me that there was hope for the .15 sized models after bad experiences with heavy kits of the Ringmaster Jr. and the Jr. Flite Streak that would not fly well unless moving way too fast to fly smoothly. If the wood in the Umland kit is decent at all, I can recommend this set up.

Definitely make the flaps operable.

By the way, it was an article on learning to fly stunts by Larry Renger (our own Designman) in AAM which used the Shark .15 as a demo model that convinced me to try the Jetco kit after the bad experiences with the other two planes. I wonder why he has yet to chime in here.

LA-15

OS: I would agree with all you said, except I think an 8-6 is too much for a Fox 15 baffle engine. Currell

Currell,

Normally I'd agree with you. I tried the 8×4, but it just didn't do it for me. I should mention that I ran the engine with a somewhat less than desirable fuel according to Fox and the various other folks who have reporting that engine. I was using SIG Mike Stott Champion 5%/29% all castor fuel and a Fireball hot RC short plug. It worked well here and the engine had plenty of power running the 4-2-4.

What is the target weight for this airplane? Mine is going to come in at about 21 oz. That is with a Fox slant plug .15 with muffler and spinner. Heavier than I had hoped, sad but true. Whew, what a relief. I recalculated, and it is going to weigh slightly less than 20 oz.

I'd say somewhere around a pound. 21 ounces isn't fatal, however.

I'm running a Norvel BigMig .15 in my U-Key 15 and it hauls it around nicely on an APC 8x4. After a dozen runs (and two crashes) the Norvel is starting to settle down. I find it a little difficult to start tho...

We use an FP 15 on my son's Streak Trainer. It starts wonderfully but doesn't have the power of the Norvel.

The only thing I don't like about the Norvel 15 is the spring mounted muffler. I understand the new ones use a clip arrangement plus you get the Revlite piston/cyl setup.

Thanks to all for the responses!
Was trying to figure out if I needed to get a new engine, or use one of the ones I have already.
I have a few slant plug Fox 15s, a steel fin Fox 15, And possibly an OS 15 from the 35S era. So I think I can make out with one of the Foxes! Will try the steel fin one first.
I will hook up the flaps, and use the big BC/Horns.
Thanks, again!
Bill <><

I scratchbuilt one from the Jetco plans. 19 oz, flaps, TD 09, Cox 7 x 3.5 prop. Sig Champion 10% nitro, 20% 50-50 oil, 55 ft 012 cables. A really fun airplane. I have one of Walter's kits and am well impressed. I will use one of my wooden 4 inch bellcranks that I make for 1/2A's (built a hair stronger) The one in my original Shark 15 survived a 30-lb pull test.

One mistake I made was not making a adjustable wing weight box. I built in too much weight in the outside wing and ended up poking epoxy coated BB's in through the adjustable leadout slot in the inside tip to get it to stop hingeing.

I'm thinking of trying a Cipolla 09 diesel when I build Walter's kit.