Author Topic: Day Zero of a new project. (Read 3773 times)

Paul Smith · « **on:** September 15, 2010, 06:44:25 AM »

Pitchers now. text later.

Larry Renger · « **Reply #1 on:** September 15, 2010, 12:39:07 PM »

How big is that thing? A really interesting project!

Paul Smith · « **Reply #2 on:** September 15, 2010, 06:46:32 PM »

25" span and 23" long, with a TeeDee .049. It's an F-86 Sabre for a profile scale thing in 10 days.

LARRY RICE · « **Reply #3 on:** September 15, 2010, 08:39:07 PM »

Dick Sarpolus designed this awhile back and we currently kit that model. Good Luck
Larry

Larry Renger · « **Reply #4 on:** September 15, 2010, 10:08:31 PM »

It's going to be FAST!!!

Paul Smith · « **Reply #5 on:** September 16, 2010, 07:03:37 AM »

Quote from: LARRY RICE on September 15, 2010, 08:39:07 PM

Dick Sarpolus designed this awhile back and we currently kit that model. Good Luck
Larry

I hadn't noticed this up unti now. However, your (Dick's) design is modified quite a bit to make it stunt. Mine is for a scale event and it probablity won't stunt as well, bit I still hope to do loops and inverted.

roger · « **Reply #6 on:** September 16, 2010, 05:34:11 PM »

nice

Paul Smith · « **Reply #7 on:** September 17, 2010, 07:22:19 AM »

Day Four.

Haste makes waste. I jumped on this with a 3-view I pulled off Wikipedia. Later on, I referenced a some color documentation from "History of the U.S. Air Force" and found that the two disagree by A LOT. I guess by scale rules I could have proceeded to us the Wiki drawings and presented them, right or wrong. But I have more faith in the USAF drawing, and besides, they make for a more flyable model.

So I reworked the wood and got on with it. On bigger models, I study 'em longer and don't cut wood within the first three hours.

The tailplane is plywood, on the theory that these planes are typically nose heavy and I might as well get the strength. Moving those swept flippers will be a bit of a challenge. One that need to be proven in 1/2A before going bigger.

Jeffrey Olijar · « **Reply #8 on:** September 18, 2010, 09:36:46 PM »

that is my all time favorite airplane. Been thinking about getting the kit for awhile. I have too many projects though.

John Rist · « **Reply #9 on:** September 18, 2010, 09:51:48 PM »

With the wings sweptted that far back how do you handle the wing tip line guide? Also where is the CG?

Paul Smith · « **Reply #10 on:** September 19, 2010, 05:49:20 AM »

Good questions.

One good reason to try this stuff on a cheap 1/2A before going bigger.

roger · « **Reply #11 on:** September 19, 2010, 07:17:04 AM »

maybe check with sarpules he built one.

Paul Smith · « **Reply #12 on:** September 19, 2010, 04:36:53 PM »

No. I calculated the MAC to locate the bellcrank & leadout guide. It will be a sort of boom that that extends in front of LE and has several holes to chose from.

The outboard tip weight is sticky back lead tape, covered with thin balsa for painting.

Paul Smith · « **Reply #13 on:** September 20, 2010, 06:23:33 AM »

This was Day Three. I'm a couple days late on the posting. Last pre-paint pix.

I got distracted on the other events at the upcoming contest: OTS and Musciano hollow log.

Paul Smith · « **Reply #14 on:** September 20, 2010, 06:25:42 AM »

Now, back to real time:

Bill Heher · « **Reply #15 on:** September 20, 2010, 08:09:31 PM »

My friend Tom's version of Dick Sarpolus F-86. Set up for Tee-Dee / Norvel and plan on using balloon tank. I have one also- but I'm not as far along / look as nice. Mine also has a warped wing that needs some steam-n-twist action.

The swept elevator hinge line was dealt with by the simple method of making it straight. May not be true to scale- but I'd rather loose a few possible points and have a simple and free moving control system. They have to fly as well as look good!

Bill Little · « **Reply #16 on:** September 21, 2010, 07:04:26 AM »

Hi Paul,

I guess you are going to use two elevator horns?

Mongo

Paul Smith · « **Reply #17 on:** September 22, 2010, 11:11:47 AM »

Yes, two horns and pushrods.

Finished weight looks like 9.3 ounces, compared to 5.2 for my new "Bullet" hollow log and 4.8 for my soon-to-be-retired worn out "Golden Hawk".

Somebody has to design something new some time.

My latest stumbling block is the lettering & USAF roundels. I know how to do it right, but I don't have time. We need to cut corners, like Battlestar Gallactica.

I'm workin' like a madman to get this stuff assembled and tested by tomorrow night.

I expect to cut back that supersize leadout guide when I get the plane checked out.

minnesotamodeler · « **Reply #18 on:** September 22, 2010, 09:17:47 PM »

So 2 pushrods, one from each side of the BC! Interesting...no problems with the geometry, getting both elevs. coordinated?

Tim Wescott · « **Reply #19 on:** September 22, 2010, 10:21:17 PM »

Quote from: Bill Little on September 21, 2010, 07:04:26 AM

I guess you are going to use two elevator horns?

If you didn't already have it done I'd suggest lucky boxes -- and a watchmaker's loupe.

Paul Smith · « **Reply #20 on:** September 23, 2010, 04:20:16 AM »

40 degrees of sweep is waaa-aay too much to expect with a lucky box.
Personally, I would only trust a lucky box to compensate for the misalignment of a straight hinge line. This would a LOT of wire scrapping against plywood.

The bellcrank and control horns both have equal throws, so the movement should be equal. I incorporated "adjustment kinks" in the classic Scientific style to get them level. There are NO pushrod guides. One side or the other is always in tension. Remember, the air long on each rod is only half of the total.

As with everything, flight testing is pending.

"Even in the contest between man and steer, the outcome is not certain"

No country for Old Men

John Desrosiers · « **Reply #21 on:** September 25, 2010, 06:08:50 PM »

Can you post close up photos of your bell crank set up. I,m thinking of building a profile by plane. Thanks

Paul Smith · « **Reply #22 on:** September 25, 2010, 06:50:41 PM »

I didn't get a real good picture of the 1/2A bellcrank, but here's one of 40-size version that's been in service, successfully for two seasons.

Basically, it's just a regular bellcrank with an additional output on the opposite side. It allows two, or even four pushrods to drive elevators and flaps independently. Thus swept trailing edges and/or dihedral can be accommodated. Plus, you get independent adjustment and the load is distributed over two or four smaller pushrods.

John Desrosiers · « **Reply #23 on:** September 25, 2010, 06:55:11 PM »

How do you mount it into a profile balsa fuse.

Bill Adair · « **Reply #24 on:** September 25, 2010, 08:44:52 PM »

Paul,

Wow, quad redundancy! Great idea.

Bill

john e. holliday · « **Reply #25 on:** September 26, 2010, 07:36:55 AM »

Quote from: John Desrosiers on September 25, 2010, 06:55:11 PM

How do you mount it into a profile balsa fuse.

Trying to be nice here, but go look at the pictures a little closer. You may have to enlarge them. Should have had this before I started the King Sweep. Also may start on the Palmer Hi-Boy.

Paul Smith · « **Reply #26 on:** September 27, 2010, 06:29:11 AM »

Quote from: John Desrosiers on September 25, 2010, 06:55:11 PM

How do you mount it into a profile balsa fuse.

As close to the CL as possible.

Inboard side against a plywood plate.
Fore-and-aft, spruce blocks the same thickness as tha axle.
Finally an outboard cover plate to trap the whole works.

Paul Smith · « **Reply #27 on:** September 27, 2010, 06:34:19 AM »

I flew it twice Sunday. It went well, although still a bit nose heavy. By scale or racing or carrier standards, a good flyer. Still not quite there for stunt or combat.

Tail heavy on the first flight is the end of he world. I can still move the fuel tank aft, then it comes down to tail weight. I think lead tape can be made to look like a titanium exhaust outlet.