Take apart Tempest Build

[Chris_Rud]

Hi All,

I'm working on finishing up my full scale pilot license this summer and I wanted to build a plane that I can fit into the back of my Dad's Skyhawk. This CL plane is the same numbers as my current Typhoon but will have a different flap ad wing tip shape and a different shaped rudder to resemble the Hawker Tempest.

I have looked around for about a year for a take apart system that I like. The metal take apart system offered by the Yatsenkos is a great system but I wanted to try and find/create a system that has limited amounts of metal. Tom Morris sent me a picture of what he has been working on and I thought it was a good idea. My only concern was that with how much I fly the system would wear out. When I was with Billy for the weekend we drew on a napkin a version of Tom's new system but with a few other ways to stop the wearing and ways to attach it to a lost foam system a little better. Billy said why hasn't anyone thought of this in the last 40 years. Good job Tom!

My ultimate goal is to build a take apart plane at 59 oz which is an oz heavier than my current plane. I start first on the tail since I knew if I did a moulded leading edge I could save so weight. (thanks Doug!) The tail with hinges and the horn came out at 1.5 oz. Its an oz lighter than the tail on the current plane. I know Im going to gain about the much when I have to make the tail removable to it will be a wash.

I have also attached images of how far I'm with the spar development. I'm guessing that the wing take apart system is 1-1.5 oz. Its hard to tell since there are so many common pieces that are in both a regular wing and the take apart wing. Its going to be a slow but steady.

-Chris

[Chris_Rud]

Some more pictures...

[Chris_Rud]

Last batch...

One thing that I did was make a lost foam cradle specific for this fuse width and glued it to a piece of ply that I can weigh down the ply and it will stay perfectly straight.

[john e. holliday]

Well it is a start.   Love how you guys think out side the box.

[wwwarbird]

 Chris and Doc, will we see you guys in Polk City next weekend? Really hoping to check out that Typhoon!

[john e. holliday]

I'm trying hard for the family to let me go Sunday.

[Doug Moon]

Chris,

It looks good so far!!

Love that leading edge of the stab!!!!

Keep the pics coming. Especially the spar setup as it comes together.

Thanks
Doug

[Chris_Rud]

Chris and Doc, will we see you guys in Polk City next weekend? Really hoping to check out that Typhoon!

Yep I plan to be there.

-chris

[Chris_Rud]

Chris,

It looks good so far!!

Love that leading edge of the stab!!!!

Keep the pics coming. Especially the spar setup as it comes together.

Thanks
Doug

Will do. My goal is to have wings mostly constructed by next week. We will see if that happens but the ribs are already cut I just want to take it slow and think through the integration of the take apart system.

-chris

[Chris_Rud]

Over the last few days I have made some progress. I sanded the ribs last week but I had to figure out the best way to transfer the tapering spare to the first 4 ribs. One thing I ran into is that the joint at the first rib was only able to touch at the 1/4 square stock spar and wasn’t able to join the first rib to the phenolic tab since the phenolic and bass wood from the fuse spar is in the way. I’m not sure if the pics are going to be able to see that. So I ended up adding a half rib right after the screw that holds the joint more firmly. Any how it took about 4 hours to figure out and cut the necessary slots in the ribs.

Last night I test fit the ribs together and had to file away some of the plywood doublers for the gear and the 1/64 laminated ply on rib 1. I then layed in the remainder of the ribs and glued the wing together. It went very smoothly.

I took the wing out of the cradle and took out the take apart piece that goes through the fuse and everything looks better than I expected. I believe it is plenty strong. In fact I probably didn’t need the 1/16 phenolic that goes through the fuse and could have use basswood with a t-nut drilled out to stop the basswood from wearing out.

The leading edge molds are drying so hopefully by the end of the week I will be done with the wing. More coming soon.

[Allan Perret]

Tom Morris sent me a picture of what he has been working on and I thought it was a good idea. My only concern was that with how much I fly the system would wear out. When I was with Billy for the weekend we drew on a napkin a version of Tom's new system but with a few other ways to stop the wearing and ways to attach it to a lost foam system a little better. Billy said why hasn't anyone thought of this in the last 40 years. Good job Tom!
-Chris

Did not know Tom had a new system, what does he call it ?  Is this system in your pictures below ?

[Curare]

Any reason for using phenolic for the tabs?

[Chris_Rud]

Did not know Tom had a new system, what does he call it ?  Is this system in your pictures below ?

Yes Allen, this is a version of his system. He didn't name it (or tell me the name) he just emailed me an image and I worked from that.

-Chris

[Chris_Rud]

Any reason for using phenolic for the tabs?

The phenolic was Billy Werwage's idea. When we discussed the system he recommended the phenolic since it wouldn't wear. Now that I have done it I don't think the phenolic on the fuse spare is necessary if you used a T-nut and just drilled out the threading so it was more like a shaft then a nut it would accomplish the same thing but be lighter. The phenolic on the wing tab I believe is very necessary. The joint is so tight and I can't see how it would fail or wear.... We will see but I seems incredibly strong even without the sheeting and other minor tie-ins that I still plan on doing.

-Chris

[Doug Moon]

Hello Chris,

I was looking over the pics again. It would seem you would want the phenolic tab that is attached to the spar on the wing to slide in a butt up against the wood that is under the phenolic spar going through the fuse??  It looks like in the pics there is a gap there. Or is this not going to be an issue?

Just curious.

[Chris_Rud]

Hello Chris,

I was looking over the pics again. It would seem you would want the phenolic tab that is attached to the spar on the wing to slide in a butt up against the wood that is under the phenolic spar going through the fuse??  It looks like in the pics there is a gap there. Or is this not going to be an issue?

Just curious.

Good question. I went back and fourth on this. I had to leave some room on this joint so that I could get the alignment right for the spar on the foam cradle. It needed to swivel a bit. My plan was to shim some wood in there to make the joint perfect but now I'm thinking its unnecessary and I actually have a hard time getting the pieces apart so I will be sanding down the front lip to the top and bottom tabs on the fuse spar. That way the piece will slide in a little better. Just about 3/32 of an inch. The phenolic is slightly smaller then the 4-40 screw so it has to be screwed in and that is what keeps everything aligned.

Thanks!
Chris

[Chris_Rud]

Here is last nights progress. I like to pack in the center to make sure I never have an issue. I lay .007 unidirectional carbon across the spare to strengthen it and I normally go a few bays past the gear. Got the leading edge sheeting and the wing is really starting to feel strong. Moving onto the cap strips and shear webs and then I will be calling the wing done.

-Chris