Author Topic: Hope I chose right (Read 3504 times)

Bill Smith · « **on:** April 07, 2013, 11:53:14 AM »

I decided I was going to use the Wen-Mac.
I think small and light will work. Needs to be able to do the beginner pattern.
18 inch span, 3.9 ounce, 6-3 press wood tornado prop on a Wen-Mac .049.
Spiderwire lines.
Any advice?

Paul Smith · « **Reply #1 on:** April 07, 2013, 02:13:33 PM »

If you succeed in getting that Wen Mac to run you are one of a select few.
Once it's running you'll be flying a long time on that tank.

Larry Renger · « **Reply #2 on:** April 07, 2013, 02:26:06 PM »

Change that to taxiing.

Bill Smith · « **Reply #3 on:** April 07, 2013, 02:36:12 PM »

Yes, taxiing may be right. I think it will fly and probably loop but it may have to be under 2 ounces for a wen-mac to do a square. and since the engine weighs 2ounces by itself that may be impossible.
the aluminum covers a balloon that hold about 3/4 ounce.

Larry Renger · « **Reply #4 on:** April 07, 2013, 09:31:03 PM »

Actually, that is a very nice looking plane. Is it a Pee Wee Pup, or your own design?

Good luck on the power output. I think it should fly as you expect.

Bill Smith · « **Reply #5 on:** April 07, 2013, 09:40:08 PM »

It's sort of modeled around the plastic fused fire baby. tried to keep it light.

dennis lipsett · « **Reply #6 on:** April 08, 2013, 03:19:29 AM »

I'd get rid of the 6/3 prop even though that gumwood prop is light. A 5/3 narrow blade will work better. I've seen models such as yours fly and do basic maneuvers with a Wen Mac. I flew a couple of them 60 years ago myself. They start and run fine with a hot plug and battery. the glow head Testors version were better though.

Dan Berry · « **Reply #7 on:** April 09, 2013, 04:06:09 PM »

Which Mark Wen-Mac are you running?
I'll agree with dropping the prop to a 5x3. Coz black is a decent choice. TF 5 1/4 x 3 would also be a good one.

Tim Wescott · « **Reply #8 on:** April 09, 2013, 04:13:08 PM »

I dunno about the Wen-Mac, but I've gotten a lot better "stunt run" from cox reedies with a 6-2 than anything else -- a 6-2 prop gives you lots of acceleration off the ground, without a lot of top end but with lots of grunt going uphill.

I have a baby Ringmaster running a Testor's Wen-Mac, with a black 6-3 on it. It's a nice sport flier but it doesn't really stunt.

Trostle · « **Reply #9 on:** April 09, 2013, 05:25:40 PM »

Quote from: dennis lipsett on April 08, 2013, 03:19:29 AM

I'd get rid of the 6/3 prop even though that gumwood prop is light. A 5/3 narrow blade will work better. I've seen models such as yours fly and do basic maneuvers with a Wen Mac. I flew a couple of them 60 years ago myself. They start and run fine with a hot plug and battery. the glow head Testors version were better though.

Not only should you change that prop for the given airplane, but that Tornado Presswood is almost a collectors item. It would be a shame to destroy it.

There have been some fiber glass copies of this (from ACE - no longer available) but others have made carbon copies of this prop. That prop on a Tee Dee or Medallion and a good 1/2A stunt ship is a great combination.

The message is "Save the prop!" If you want to dispose of it, maybe we can work out a deal.

Keith

Bill Smith · « **Reply #10 on:** April 09, 2013, 10:48:52 PM »

Those props can't be collector items. at least not until I use up the 12 6x2s and 24 6x3s I have. And I only use them on cubs and wen-macs.
I should be about 97 then only 37 years to go.
I don't think a wen-mac will wind up the revs you need to stunt with a 6x2. They are OK for free flight though.

George · « **Reply #11 on:** April 10, 2013, 10:38:21 AM »

Quote from: Bill Smith on April 09, 2013, 10:48:52 PM

Those props can't be collector items. at least not until I use up the 12 6x2s and 24 6x3s I have. And I only use them on cubs and wen-macs.
I should be about 97 then only 37 years to go.
I don't think a wen-mac will wind up the revs you need to stunt with a 6x2. They are OK for free flight though.

I use the old "Plasticote" and other wood props for old engines with weak crankshafts that include the prop shaft...like early Coxes, Spitzy, etc.

George

Bill Smith · « **Reply #12 on:** April 10, 2013, 01:19:03 PM »

Your right, they have no mass so they can't break anything.
tried one one a TD and had a hell of a time getting it started, there wasn't adequate mass for the high compression TD.
most of the time it would just oscillate.

Ron Cribbs · « **Reply #13 on:** April 10, 2013, 02:36:59 PM »

Nicely done!

I think the best choice of engine would be a Cox Medallion .049. Not as powerful as a TD, but plenty of umph to pull it around.

Not sure if that slab wing is able to do the beginner pattern although you may be able to pull it off.

Where in the world did you get that tank? It's amazing! I am converting a Li'l Jumpin Bean to run on a TD and that tank would be a perfect choice.

Edit: My go to prop is a Master Airscrew 6x3 that I cut down to 5.5x3 it's large enough to keep the revs where I want it and plenty of torque to pull it through manouvers.

Bill Smith · « **Reply #14 on:** April 10, 2013, 07:38:17 PM »

That is not really a tank. It is an aluminum cover for a balloon. The thing that looks like a tube on the top is a screw head.
and the back side slips into a slot in the canopy.

By the way the lil jumpin bean is a great little plane that's where I borrowed my pilot.

fred krueger · « **Reply #15 on:** April 10, 2013, 08:07:58 PM »

I will do a video of this plane when Bill has the first flight.

Fred

Jim Thomerson · « **Reply #16 on:** April 11, 2013, 10:22:47 AM »

I have an older WenMac on an Ebineezer sport FF, and it is grossly overpowered. I finally cut a piece of small fuel line and put it in the venturi. Hopefully that will tame it down. I was very surprised at how well the WenMac handles and how powerful it is.

Mike Lauerman · « **Reply #17 on:** April 11, 2013, 03:59:33 PM »

I was impressed by this airplane, and taken by its aluminum tank cover. (glare in pilot's eyes notwithstanding, don't paint it flat black; Polish it!)

Glad to hear it's scratchbuilt...and from such a famous design.

Bill Smith · « **Reply #18 on:** April 12, 2013, 06:15:15 PM »

Well, fired up the wen-mac mark 3 today and it ran great. Started on the third flip, needled nicely. Of course I could not find my Tac and I looked everywhere.
If I buy a new one the old one will show up within the hour.
So I cheated I used my electronic guitar pitch gauge and got the pitch for the cox product motor on my Firebaby http://stunthanger.com/smf/index.php?topic=29194.0 and the Wen-mac was just flat# of that.

That was with the 6x3 prop and 25% sig 50/50. I was surprised, my Ok cub was slower. http://stunthanger.com/smf/index.php?topic=30820.0
When I find my dam Tac I get some actual numbers, but it looks good right now.
Hope the weather is ok this weekend.

Bill Smith · « **Reply #19 on:** April 16, 2013, 06:48:32 PM »

Flew it today. Had it on 28 foot lines just to be safe.
Fred launched it, it rolled less than 3 foot and climbed out.
Caught me totally off guard I was expecting a half lap windup.
It was breezy and the engine needs some down incidence but I did inside loops, wing over, flew inverted and did a very bad square
all at under 2.85 sec laps.
First flight of the year, got a little dizzy.
A little twitchy, but with longer lines and some trimming, I think I have a winner.

By the way, with 1/2 oz of fuel, Fred had to cut out several minutes of boring.
And this flight would not have been possible without using my Cox thimble drome. yellow red and clear, Pro Stunt handle.

john e. holliday · « **Reply #20 on:** April 17, 2013, 10:01:45 AM »

I like the video.

Jim Thomerson · « **Reply #21 on:** April 17, 2013, 01:34:02 PM »

Do the math and figure out the line length to get your lap times over 4 seconds, and you should be able to fly it much better. I did it for you, 39 feet should do it.

Bill Smith · « **Reply #22 on:** April 17, 2013, 04:41:56 PM »

I reduced the elevator throw to 30 deg. from 45deg.
and next time the line length will be somewhere around 39.2982 ft give or take a little.
I also seem to have a very small warp in the wing to fix. that might have caused some of the hunting.
Hell. Who am I kidding I'm just happy it flew as well as it did.

In reality 39 ft may be too long. with the plane only weighing 4 ounces there is almost no feel for the model as it is.
Might try 32 ft and rich it up a little.

Larry Renger · « **Reply #23 on:** April 17, 2013, 10:04:22 PM »

If it is hunting, consider the ratio of handle spacing to bellcrank size. They should be nearly equal to no more than 1.25:1 . Of course I also need to tout my exponential handle design here, as that is exactly the situation it was invented to cure! See the rsmdistribution.com website to order one. There is even a hard point version available now!

Jim Thomerson · « **Reply #24 on:** April 18, 2013, 07:22:12 AM »

I'm actually an incrementalist, so I applaud your decision to sneak up on the 39 ft line length. You may need some nose weight, as my 1/2As were pretty reliable as coming out tail heavy. Cutting down the elevator throw is a good idea.

Bill Smith · « **Reply #25 on:** April 18, 2013, 10:05:48 AM »

fancy handle? No.
I don't want to get too fussy on this project. I have made much better 1/2a planes for this annual contest and on occasions have been accused of over doing it.
I have made a 32 inch nobler, A 42 inch Bearcat, 2 Fierce arrows and Pinto.
This time I am trying to do it as I would with the knowledge and resources I had when I was say 10-12.
plastic handle, string, cheap motor, balsa and paint.
My Handle

George · « **Reply #26 on:** April 22, 2013, 05:29:12 PM »

Bill,

I have one of those Cox handles...but I would probably replace the old oil-soaked Dacron line before using it. Bought it new in the mid fifties.

George

Howard.Y · « **Reply #27 on:** April 22, 2013, 06:54:41 PM »

You have a 42 inch Bearcat is that the same plane as the Barecat by Bob Baron? If so can you post information on it?
Howard

Bill Smith · « **Reply #28 on:** April 23, 2013, 06:25:58 AM »

Howard
My memory is messing with me, its 40.5 inch wing span.
What info do you need.
This one originally flew with a Norvel .049. It flies great but a .061 would be easier to deal with. It had to be screaming lean. I flew it on 48 ft lines.
As you can see now it has been converted to electric.
It weighs 13.5 ounce with the Norvel running on a bladder. I was burning up a glow plug every 5-6 runs.
Maybe I needed more nitro and oil?
But it is easily the best flying plane I have, that's why I am going to try it electric this year.

Note, Since I only flew it in 1/2a competition I never really practiced long enough to get really good with it but I did find that 14 ounce and this many square inches are not the greatest combo on a windy day.

Bill Smith · « **Reply #29 on:** April 23, 2013, 06:38:29 AM »

George

This handle is perfect for spider wire.

Dan Berry · « **Reply #30 on:** April 23, 2013, 07:23:24 AM »

Quote from: Bill Smith on April 23, 2013, 06:25:58 AM

Howard
My memory is messing with me, its 40.5 inch wing span.
What info do you need.
This one originally flew with a Norvel .049. It flies great but a .061 would be easier to deal with. It had to be screaming lean. I flew it on 48 ft lines.
As you can see now it has been converted to electric.
It weighs 13.5 ounce with the Norvel running on a bladder. I was burning up a glow plug every 5-6 runs.
Maybe I needed more nitro and oil?
But it is easily the best flying plane I have, that's why I am going to try it electric this year.

Note, Since I only flew it in 1/2a competition I never really practiced long enough to get really good with it but I did find that 14 ounce and this many square inches are not the greatest combo on a windy day.

Needed a head gasket or two.

Howard.Y · « **Reply #31 on:** April 23, 2013, 10:37:30 AM »

Bill, Looks great. Could you disclose the electric set up. Weight ready to fly, motor ,batteries, line size and lap times?
Thanks, Howard

Bill Smith · « **Reply #32 on:** April 23, 2013, 12:12:20 PM »

Do not take my setup as a recommendation of anything. I have NO experience with electric before this.
That said the motor and speed controller are E-Bay specials (probably made in china).
20 amp speed controller, 2 cell 7.4v, 800ma, 20C battery, motor is running a 6x4 APC electric prop and is rated for 2600kv
I have not flown it yet but on the ground I can get 16500rpm and about 7 mins run time.
It now weighs 17.5 ounce, the battery is rubber banded to the bottom of the wing just behind the CG point.
I forget the name of the timer right now.
Its proof of concept I will refine it if it seems to work the way I hope it will.

George · « **Reply #33 on:** April 23, 2013, 05:57:29 PM »

Quote from: Bill Smith on April 23, 2013, 06:38:29 AM

George

This handle is perfect for spider wire.

Good idea. Spider wire had not been invented last time I strung it.

George

John Rist · « **Reply #34 on:** April 25, 2013, 07:17:30 AM »

Quote from: Bill Smith on April 23, 2013, 12:12:20 PM

Do not take my setup as a recommendation of anything. I have NO experience with electric before this.
That said the motor and speed controller are E-Bay specials (probably made in china).
20 amp speed controller, 2 cell 7.4v, 800ma, 20C battery, motor is running a 6x4 APC electric prop and is rated for 2600kv
I have not flown it yet but on the ground I can get 16500rpm and about 7 mins run time.
It now weighs 17.5 ounce, the battery is rubber banded to the bottom of the wing just behind the CG point.
I forget the name of the timer right now.
Its proof of concept I will refine it if it seems to work the way I hope it will.

You may get away with a smaller battery (save weight). 7 minutes on the ground will increase when the motor unloads as it goes airborne. 5.5 minute flight time should be enough. I assume you can set flight time with your timer. Is every thing running cool?

Bill Smith · « **Reply #35 on:** April 25, 2013, 11:52:29 AM »

Yep, cool as can be.
and yes, the timer can be set for a shorter time but since I have no idea what I'm doing for now I will leave it.
I must make a correction here, the battery is 1500ma not 800ma.

john vlna · « **Reply #36 on:** April 25, 2013, 12:28:06 PM »

Bill,
Since you bought the motor, etc, as a set it likely will be OK. A rule of thumb that has proven to work is to not exceed 3 Watts/gram of motor weight. i.e a 50 g motor = 150 watts.

Also keep you current drain less than 80% of the battery capability. A 800 mah, 20c battery can continuously draw 0.8 x 20=16 amps Try to stay under 12 or 13 amps.

These high KV motors like to suck in the amps.
John

Howard.Y · « **Reply #37 on:** May 06, 2013, 08:40:40 AM »

Bill, have you flown the electrified Barecat yet? If so was there any difference in performance or handling ?
Howard