Author Topic: Armourized Tutor "Soft" tank mount (Read 4779 times)

Clay Schmidt · « **on:** September 16, 2006, 07:54:08 PM »

This is a continuation of the tank mounting thread in the open forum.

I began building the second fuselage today. I'm using a different process on this one as I didn't know what I wanted on the first one, and much of the build was an after-thought. This time around the build is going much smoother.

You'll need the tank you are going to use ready to install. Measure it up and use those dimensions to draw the box. I draw using Model Cad. After I had the parts drawn I printed them out on a sheet of sticky label paper.

Clay Schmidt · « **Reply #1 on:** September 16, 2006, 08:00:49 PM »

I cut the box parts out of lite-ply. Before I remove the lable from the part I like to take a #11 blade and make a light score along the center & reference lines.

I glued the front and back onto the bottom piece taking care everything was square.

I then prepare the balsa blocks for the lord mounts. The blocks were faced on the back side with lite-ply and a blind nut for the lord mount. The side was faced with 1/64th ply so I would have a hard edge around the perimeter of the tank opening. The blocks were then adjusted for tank depth and glued to the box.

Clay Schmidt · « **Reply #2 on:** September 16, 2006, 08:19:02 PM »

After the blocks were dry I sanded their tops flush to the sides of the box and added the top.

Time for a test fit of the tank. Everything looks good here so I then added the mounts for the hatch cover.

Clay Schmidt · « **Reply #3 on:** September 16, 2006, 08:30:46 PM »

I sanded the box, check for square, then wrapped it in 1/16th ply. The ply will provide a hard edge and a recess for the hatch cover. It will also add considerably to the stiffness of the nose. The edges of the 1/16th ply will be blended into the balsa triplers when the nose is carved down.

I'll have more pictures tomorrow.

Clay

wmiii · « **Reply #4 on:** September 16, 2006, 08:45:49 PM »

Can't wait to see the finished product, looks awfully neat so far,very nice workmanship.

Walter

Clay Schmidt · « **Reply #5 on:** September 17, 2006, 12:37:16 PM »

Here I cut the front of the fuselage to accept the tank box. A test fit and I'm ready to laminate the fuselage with 1/64th ply. I'll do this before I glue the box to the fuselage.

Clay Schmidt · « **Reply #6 on:** September 18, 2006, 01:11:55 PM »

The fuselage has been laminated with 1/64th ply. The fuslage triplers and firewall have been prepared. It's time to glue this sucker together.

First I position the tank box into the fuselage, center it up, make sure everything is square, then glue it with thin CA.

I mixed up some slow set epoxy,& thinned it with denatured alcohol. Brush the thinned epoxy to both the triplers and fuselage.The triplers are then wrapped tightly to the fuselage. Masking tape is one of the best clamps you can buy.

We'll let this dry. More pictures later

Clay

Clay Schmidt · « **Reply #7 on:** September 18, 2006, 07:41:02 PM »

Thank you Ty. It is working pretty well this go around. I just wish all my projects went this smoothly.

The front end has been sanded square and flat. Go easy here as it is very easy to sand in a bow. Use good sharp sandpaper in a fairly rough grit. I use 80. Check your progress often with a tri-square. Reference marks are made to align the firewall.

The firewall is now glued with slow set epoxy. Work epoxy into the balsa with a fairly stiff brush such as a acid brush. Coat the firewall with a thin coat of epoxy and slap it together taking care to align the firewall to your marks. Tape it to hold while it dries.

I put a little release wax in the threads of the socket screws and installed them into the blind nuts to prevent epoxy from oozing into the thread. After the epoxy has set but not cured I'll back them out and run a clean screw with denatured alcohol into each one to make sure they are nice and clean.

Tomorrow I'll start carving. .

Clay Schmidt · « **Reply #8 on:** September 19, 2006, 12:08:59 PM »

It's time to carve this baby down. Obviously we'll use the firewall for the shape we want. We want to transfer this shape back so the nose will have a constant thickness and shape to the point where it tapers sharply to flat portion of the fuselage.

I learned a trick years ago from an article by Bob Hunt and Dean Pappas in Flying Models. They were carving leading edges on a pattern plane wing and used reference lines to accurately shape the leading edge. I simply adapted the technique to this project.

First I drew the reference lines on the top and sides of the nose just outside the firewall so I could lop of the corners. I carved the corners just to the reference lines and sanded them smooth.

I then drew a second set of reference lines and repeated the process on the remaining large corners.

Now that the bulk is gone I was able to take my sanding bar with new 80 grit and blend everthing together. After the sanding with the 80 grit was done, I final sanded with 220 grit "shoe-shine" style. This will get rid of all those pesky ridges created by the hard ply edges. Notice how the shape of the firewall was transfered to the rear of the tank box.

Now it's time to make the hatch cover. More pictures later.

Clay

Clay Schmidt · « **Reply #9 on:** September 19, 2006, 03:03:23 PM »

Ty,

This the original Tutor modified by Jim Armour. Here is a link to the reprint of the 1986 Model Aviation article by Ted Fancher. You'll need to go on to page 9 to get the whole description. I really liked the airplane and since I'm just getting back into c/l after a gazillion years I thought maybe this might be a good start.

http://www.aeromaniacs.com/Fancherized/pages/p8_jpg.htm

Clay

Clay Schmidt · « **Reply #10 on:** September 19, 2006, 10:19:12 PM »

Time to make the hatch cover.

This satin mylar stuff sure is handy for making patterns for parts that go into holes. After the pattern was made I traced the part onto 1/32 ply and poked the holes for the mounting screws.

I then glued the 1/32 ply piece onto a piece of 1/2 balsa, taking care not to get glue around the screw holes. The balsa was then sanded to match the ply backing. A drill press was used to opened up the holes to accept 4-40 screws. After that I lined the piece with 1/64th ply to provide the hatch with hard edges.
I placed the cover on the fuselage and installed the 4-40screws.

Next I took a piece of brass tubing just large enough to go over the head of the screws and sharpened it with a #11 blade. I place the sharpened tube over the screw and twist down about half way, removed the screw, cleaned out the balsa bits, re-installed the screw, and finished the cut. The process was repeated for the other three screws. After that was finished I soaked the screw holes with thin ca to harden the ply and the surrounding balsa.

After I was sure the ca was dry, the cover was re-installed on the fuselage in preparation for shaping. Masking tape was used to protect the fuselage. We don't want to mess up what we've all ready done.

The cover was worked down with a sanding bar and 80 grit paper. When I started to scuff the masking tape, the tape was removed and I finished sanding the cover "shoe-shine" style with 220 grit paper.

The last step is to make a clearance slot for the uni-flow tube and front end it is done.

Clay Schmidt · « **Reply #11 on:** September 19, 2006, 11:14:28 PM »

Well here they are, a set of twins. Now I get to build two wings, two stabs, and two fins.

Thanks for all your indulgence.

Clay

Warren Wagner · « **Reply #12 on:** September 20, 2006, 12:24:38 PM »

Quote from: Clay Schmidt on September 19, 2006, 10:19:12 PM

Time to make the hatch cover.
The cover was worked down with a sanding bar and 80 grit paper. When I started to scuff the masking tape, the tape was removed and I finished sanding the cover "shoe-shine" style with 220 grit paper.

Clay,

Great work....you make it look like something that is made to a NASA specification. Thanks for sharing the photos, and keep them coming.

I recently went throught the "shoe-shine" sanding operation of a similar situation on the nose of an "Imitation". With the amount of material that had to be removed, the operation was rather robust !! I needed another set of hands. What worked out great, was the use of my Black and Decker Work Mate. I just used a couple pieces of scrape pine to protect the balsa fuselage, and let the Work Mate do all of the holding. It was a big help.

Cheers.

Warren Wagner

Clay Schmidt · « **Reply #13 on:** September 20, 2006, 01:23:05 PM »

Warren & Ty

Thanks for the compliments, you are making me blush!

Warren,

That's a good idea about the workmate. I wished I would have thought of that, as I have one. Next time.....

Ty,

I was blessed growing up around quite a few master builders as a kid. My Dad and Bob Arnett to name a couple. I also pay A LOT of attention to the likes of Bob Hunt, Bill Werwage, Dean Pappas, Al Rabe, Ted Fancher, Robert Storick, Randy Powell, and everyone on this forum. There is a wealth of building knowledge out there to be had.

Good building practises become habit, so it doesn't matter what a guy builds. My only advice is to practise, gain experience, keep your blade and sandpaper sharp, and your reference lines straight and square.

Clay Schmidt · « **Reply #14 on:** September 20, 2006, 08:06:21 PM »

Furniture!.......... Norm Abrham!!!!!!!!

RC Storick · « **Reply #15 on:** September 20, 2006, 08:07:58 PM »

Clay you do great work! The only problem I see is how do you shim the tank up or down?

Clay Schmidt · « **Reply #16 on:** September 20, 2006, 08:19:59 PM »

Robert,

I don't. The tank mounting brackets have slots in them so I can move it up or down 1/8".

Clay

RC Storick · « **Reply #17 on:** September 20, 2006, 08:35:46 PM »

I didn't see that before, I must have bee sleeping.

Chris McMillin · « **Reply #18 on:** October 18, 2006, 11:12:27 PM »

Here is Jim's original Tutor. The photo was taken yesterday as it was the date of young Joseph Passannante's first solo flights. He made three flights.

His father Dave used a Tigre 46 to brush up on the pattern, and is using a Magnum 40 in it to teach the boys, John, 5 and Joe, 7 the finer points of control line flying.

Saturday we had Dave his boys, myself and my little boy Michael, 10 who soloed my old (his now) King Cobra, and Grandpa Jerry McMillin to help out.

Thought you guys would like to see the old Tutor is still going strong.

Chris...

Ward Van Duzer · « **Reply #19 on:** October 19, 2006, 11:55:33 AM »

As Bobby Hunt once said to me "Ward, it's ONLY a profile"!

But beautiful is beautiful!

Clay Schmidt · « **Reply #20 on:** October 19, 2006, 02:37:09 PM »

Chris,,

Man,,what a surprize! Thanks for the picture!!! It is a good looking machine.

How do you and your boys like it?

Clay

Chris McMillin · « **Reply #21 on:** October 20, 2006, 01:46:39 AM »

Clay,
I've never flown it, but Dave has had it for about 10 years and liked it fine. It has hung on the wall for a long time until lately, when he started his boys on it. My son liked it better than his King Cobra as the controls are much slower.
It looks great in the air and has weathered the ages well.
Chris...