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Speed,Combat,Scale,Racing => Rat Racing and Team Racing => Topic started by: Paul Smith on February 08, 2018, 10:25:57 AM

Title: Cosmic Wind project
Post by: Paul Smith on February 08, 2018, 10:25:57 AM
I'm trying to build a Cosmic Wind from plans.
I've had some problem because I'm using a rear exhaust engine and a centerline bellcrank.
This drove me to make a really low-profile shutoff.
I finally got it done and pressure-tested. 
I ended up using extended engine mount pads as the basis for the shutoff. 
The thick pad also gave me a little more fuel tank space.
Title: Re: Cosmic Wind project
Post by: Motorman on February 10, 2018, 04:05:56 PM
What's the plan for putting a wing on there, does it go above the bellcrank? Is this for a pressure system?
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 10, 2018, 08:21:52 PM
The pacifier was just to pressure test the shutoff.

I plan to try suction, then maybe upgrade to pressure if required.

I'm fashioning the wood form for the fuel tank today. 

The the wing will be screwed on with wood screws, then epoxied, then the wood screws will be replaced with dowels.  There isn't much stress on the wing with the fuselage bellcrank.
Title: Re: Cosmic Wind project
Post by: Motorman on February 10, 2018, 09:28:40 PM
Oh ok, low wing. Will it hang out if the tether point is down low. You could put the wing on with the inboard tip a little higher to try and keep the fuselage straight so the tank feeds right. Can I suggest a different shape for the tank? Is this for AMA scale racing? That engine likes a 6-1/4 x 4-1/4 for 30k so suction is a no go. Also if you have Dubro type blind nuts on the other side of that motor mount they will get pounded into the wood pretty quick at those revs.
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 11, 2018, 07:52:49 AM
I have aluminum mounting beams embedded in the body, threaded for 3mm.  So striping and compression is no problem.  But these also prevent me from burying the tank in the body.  The aluminum bars are also the bellcrank mount.

The flat rectangle tank is the only shape that fits under the exhaust.  It only needs to go 35 laps for Goodyear (or Rat), but more would be nice.  I think I can manipulate the variables to get the laps.  If worse comes to worse, I will be forced to move the bellcrank inboard and make a bigger tank.

I have some dihedral in the wing.  I can place the leadout guide where it needs to be make the plane fly level. 
Title: Re: Cosmic Wind project
Post by: Avaiojet on February 11, 2018, 08:27:33 AM
Paul,

The Cosmic Wind is a great aircraft to model. I had one in R/C years ago, fiberglass fuselage foam wings. 64" I believe. Sold the kit and to this day I regret it.

Here's the same model built by another modeler. A contest winner sporting CFC Graphics.

Charles
Title: Re: Cosmic Wind project
Post by: Motorman on February 11, 2018, 11:31:58 AM
The flat rectangle tank is the only shape that fits under the exhaust. 

Ok then.
Title: Re: Cosmic Wind project
Post by: Richard Entwhistle 823412 on February 11, 2018, 11:08:23 PM
I'm having the exact same engine being built right now with low timing to run without a pipe.  Why is suction out of the question?  If I can get a 6.5x5 APC up to 25000 rpm I will be happy  My OS .18 TZs gets 25,000 rpm with a 6.5x5.5 on suction but drinks fuel like the Queen Mary at flank speed.  I hope to have one less pit with Rossi and still get a good lap count. 

Later
Richard
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 12, 2018, 05:25:03 AM
I'm hoping that suction will be enough.  Mine ran very well on suction, both on the bench and on a 15 Carrier model.  It didn't seem like a gas hog on the carrier plane.

It ran OK on the RC carb, but not a chance on the gigantic factory venturi.  A 1/2" nylon spacer from the hardware store works well.  I can bore it out to find the limit once I start flying.
Title: Re: Cosmic Wind project
Post by: Motorman on February 12, 2018, 11:47:15 AM
I'm having the exact same engine being built right now with low timing to run without a pipe.  Why is suction out of the question?  If I can get a 6.5x5 APC up to 25000 rpm I will be happy  My OS .18 TZs gets 25,000 rpm with a 6.5x5.5 on suction but drinks fuel like the Queen Mary at flank speed.  I hope to have one less pit with Rossi and still get a good lap count. 

Later
Richard

If you're using the APC 6.5x5 or 6.5x5.5 you should find a better prop. They were designed for 15 size RC racing planes with giant spinners. First prop I ever copied in CF. Tried it on allot of different set ups and it was not good on anything.

Title: Re: Cosmic Wind project
Post by: bill bischoff on February 12, 2018, 12:39:56 PM
Turn it around frontwards. It'll work much better.  LL~
Title: Re: Cosmic Wind project
Post by: Richard Entwhistle 823412 on February 12, 2018, 01:15:34 PM
Flying Clown Race 15-minute feature - 345 laps - Mac Ryan - 5/29/10 - Eugene, Ore.  Record for the North West.   OS .18TZ using an APC 6.5X5.5.  How does that APC not work?  I was there.  Seven pits, pure smoke.  What is a better prop and the question "Why will the .15 Rossi not run on suction?"

Later
Richard
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 12, 2018, 01:25:01 PM
345 laps.  A very good Clown score.

I got a Rossi 15 to run on suction with a throttle for 15 carrier, but a Nelson ran better with the same setup. 
Title: Re: Cosmic Wind project
Post by: Charles Barnes on February 12, 2018, 08:08:26 PM
I believe the 345 lap race was when Clown was flown on 52' lines.
Title: Re: Cosmic Wind project
Post by: Richard Entwhistle 823412 on February 12, 2018, 08:59:04 PM
I believe the 345 lap race was when Clown was flown on 52' lines.


You are correct sir.  North West Clown rules and we are still doing it that way.

Richard
Title: Re: Cosmic Wind project
Post by: Richard Entwhistle 823412 on February 14, 2018, 10:38:13 PM
Paul
I built a tank shield from thin stainless that mounts on the rear top cover screws and a post by the tank.  After two 90 degree bends there is about a 1/8 air gap between the shield and the tank.  The tank never gets hot.  The only problem is the plane gets a bit oily and little hard to hold onto while pitting.  A shield seems a lot easier to do than moving the bell crank

I see what you mean by "gigantic factory venturi".  It measured .275 ".  I sleeved it down to .162".  My OS .18 TZs run well with a .169" sprinkler so I think I'm close at .162". The Rossi isn't a converted "cart" motor by any means.  It's built like a bear for sure.  It's a .15 that thinks it's .25.  I had an older clown on the wall that was fitted with a MVS diesel at one time.  The rear mounting holes were a perfect fit but the fronts required new holes drilled.  Balance was almost perfect. Your Cosmic Wind should go like stink.  I"m flying tomorrow with the Clown guys.  I'll let you know how fast the Clown goes and the laps.  And Yes, MM I'm using an APC 6.5X5 because it is the only brand I have that looks like it will stay together at 24,000 plus.  I would buy one of your killer props if you are selling.

Later
Richard
Title: Re: Cosmic Wind project
Post by: bill bischoff on February 15, 2018, 08:45:34 AM
Eliminator Props sells a  carbon APC 6.5x5.5 copy. Mine ran the same speed as the plastic, but with the added strength of carbon.

Bill Bischoff

(sorry to stray even farther off topic)
Title: Re: Cosmic Wind project
Post by: Motorman on February 15, 2018, 07:56:57 PM
Flying Clown Race 15-minute feature - 345 laps - Mac Ryan - 5/29/10 - Eugene, Ore.  Record for the North West.   OS .18TZ using an APC 6.5X5.5.  How does that APC not work? 
Later
Richard

Racing is like sex, all men think they're good at it.
Title: Re: Cosmic Wind project
Post by: bill bischoff on February 15, 2018, 09:08:49 PM
I hope you realize that only one of those activities has the goal of being fastest.
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 19, 2018, 02:12:17 PM
I'm out of the chop for a while on a family vacation.

This is as far as I'll get for a while.
Title: Re: Cosmic Wind project
Post by: Gordon Van Tighem on February 22, 2018, 11:47:34 PM
I have aluminum mounting beams embedded in the body, threaded for 3mm.  So striping and compression is no problem.  But these also prevent me from burying the tank in the body.  The aluminum bars are also the bellcrank mount.

The flat rectangle tank is the only shape that fits under the exhaust.  It only needs to go 35 laps for Goodyear (or Rat), but more would be nice.  I think I can manipulate the variables to get the laps.  If worse comes to worse, I will be forced to move the bellcrank inboard and make a bigger tank.

I have some dihedral in the wing.  I can place the leadout guide where it needs to be make the plane fly level.

Inboard tank out of the question?
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 23, 2018, 09:40:12 AM
The inboard tank would make a lot of drag and force more tip weight.

I'll see what happens with a low profile outboard tank.  It might give me enough laps.  I would move the bellcrank inboard before i went to an inboard tank.

The pacifier is just pressure testing the shutoff.
Title: Re: Cosmic Wind project
Post by: Les Akre on February 24, 2018, 08:33:44 PM
Hi Paul

If building to AMA Goodyear rules, you can cut a recess in the outboard side of the fuse and bury some, or most of the tank. Completely legal.

If building for some other type of Scale Race event, then probably not.

Les
Title: Re: Cosmic Wind project
Post by: Paul Smith on February 25, 2018, 07:37:46 AM
I know it would be legal, but I blocked that path with the embedded engine mounts.

I went all out to make sure the NovaRossi doesn't tear the model apart.  It only needs to go 35 laps, but more would be nice.
Title: Re: Cosmic Wind project
Post by: BillLee on February 25, 2018, 12:18:55 PM
Blocked? I see a HUGE hole through the fuselage. A tank to fit would be a piece of cake. Let it stick out the inboard side and cover with the cheek cowl. There has been at least one NATs winner that was built that way.
Title: Re: Cosmic Wind project
Post by: Paul Smith on March 18, 2018, 08:25:32 AM
After a prolonged downhill racer break, I got back in the chop & did the final assembly & alignment.  This winter has been too short and not productive enough for me.

I painted it on Saint Patrick's Day.
Title: Re: Cosmic Wind project
Post by: Paul Smith on April 07, 2018, 05:59:18 PM
I finally got my NovaRossi Cosmic Wind done.

A rather slow build for a simple Goodyear.
Title: Re: Cosmic Wind project
Post by: C.T. Schaefer on April 08, 2018, 05:45:00 AM
That's awesome Paul!!  When is the first race?    TS
Title: Re: Cosmic Wind project
Post by: Paul Smith on April 08, 2018, 08:30:00 AM
Thanks.  I'll be surprised if I ever actually race it.  I just wanted to experiment with the NovaRossi 15.

If it happens to work, the only available AMA Goodyear race that I'm aware of is down in Muncie, where I dabble in sport flying now and again.

The big hole in the middle is access to the bellcrank bolt.  I'll plug that if everything checks out OK.

The leadout guide is a piece of a big nylon control horn.
Title: Re: Cosmic Wind project
Post by: Skip Chernoff on April 10, 2018, 08:09:05 PM
Nice job on that,thanks for sharing.