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Question for HR II builders.

AX-O

AX-O

Well Known Member
Mike (G Force) and I removed my old vans fuel tanks this weekend and started modifying the wings to accept Harmon Rocket tanks. I ordered all the tank parts from Harmon but can?t figure out what the ?3/8 x 1/2 6061 T6 Bar (3ft)? is for. We can?t find it on either of the plans. Does anyone know what the aluminum bar is used for?
 
Axel

That material is for spreader bars installed vertically between the spar cap strips on the front side of the spar web. In the area of the fuel tanks, they are sandwiched between the spar web and tank attach doubler. Check Vans RV-4 drawing 12 or HRII drawing 112. If you are removing RV-4 tanks to install HRII tanks, these parts will have already been installed.

Hope this helps, Miles
 
I do not have my HRII plans in front of me but think that those stiffener pieces go further out the spar then the RV4, to help carry the load of the larger tank. You might want to call John Harmon about this issue.
 
Miles got it, I think they are sandwitched between the spar and the new tank attach doubler from Harmon. One goes where that 3/4 x 3/4 angle on the front side gets removed, and two more outboard, one at 63 1/4" and the other at the end of the attach doubler. The only issue I see now is the Harmon spar web does not have the two inboard lighting holes like these -4 spars do. The last two bars are going to span these holes so we will not be able to put all of the called out 5 rivets through it. The middle bar could be cheated inboard to the edge of the hole, but the one at the end is going to have to span the hole. Having the bell crank attachment angles right there doesnt help either.
spar1.jpg
 
Interesting that you are right there now. I've been putting off my Wing's for quite a while now that I realised the extent of the modifications that I'm gonna have to do to the spars. Scared me a little.

How many people have built Rockets off of the Ph prebuilt RV-4 spar? I know of at least one.
 
Bennair, Dunnatt

osxuser said:
Interesting that you are right there now. I've been putting off my Wing's for quite a while now that I realised the extent of the modifications that I'm gonna have to do to the spars. Scared me a little.

How many people have built Rockets off of the Ph prebuilt RV-4 spar? I know of at least one.
Click to expand...

I've done a couple.;) How can I help?

Mark
 
HR-II Spars/fuse bulhead width

Mark I Also just started the mods to Phlogiston built -4 spars. i drilled out the first few rivets to clear the new "wider" 404 bulkhead last night . They did not come out easy! I wound up using my drill press and drilling all the way through one size under then they came out in peices! Anyone have a good way to get these out without hurting the hole. Ive got 40 more in each spar to drill out for the 55 gal fuel tanks web. these are in a much thinner stack of spar bars so will probably be much easier.Do you add extra bolts in the out board ends of the 404 area or use the same # as the -4 and use double flush rivets .How did you do the double flush rivets in the spar near the out board area of the 404, since the web is already on you cant counter sink and dimple . I guess we just CS them and put the factory head on that side? Also how did you handle the rib and web stiffener spacing, since we already have the stiffeners riveted on. I dont really want a bunch of extra holes in the webs? For the oubaord ribs could we use the stiffiners as "flanges" for the ribs , then just rivet new stiffeners on in bettwen the ribs ?
Also on my fuse the #7 bulkhead is 24.25 wide and my turtle deck formers from Harmon are 23.5 . the rest of the bulkheads are wider then the Tdeck formers also. I think i can "tweak " things and make it work,any thoughts here? sorry to pile on the questions ....Any help would be great! Thanks Dan Weseman
 
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using Phlogiston pre-built spar in Rocket

I also did this. Dan already hit the trick for drilling out the rivets; drill all the way thru undersize. I got so that most would come out in one piece. I made new fuselage bulkheads from scratch so I'm not much help there. I also was early in the Rocket group and went with 40 gallon tanks; splicing in an addition to the C-doubler.
 
Rocket Science 101

danweseman said:
Mark I Also just started the mods to Phlogiston built -4 spars. i drilled out the first few rivets to clear the new "wider" 404 bulkhead last night . They did not come out easy! I wound up using my drill press and drilling all the way through one size under then they came out in peices! Anyone have a good way to get these out without hurting the hole. Ive got 40 more in each spar to drill out for the 55 gal fuel tanks web. these are in a much thinner stack of spar bars so will probably be much easier.

As Larry said, drill the head off with a 1/4" drill, then drill undersize (so a 1/8" punch will fit in the hole) but don't drill ALL the way thru. Use the punch to remove the rivet. Piese o cake.

Do you add extra bolts in the out board ends of the 404 area or use the same # as the -4 and use double flush rivets .

Double flush rivets.

How did you do the double flush rivets in the spar near the out board area of the 404, since the web is already on you cant counter sink and dimple . I guess we just CS them and put the factory head on that side?

Yep, but it matters not which side the factory head is on.

Also how did you handle the rib and web stiffener spacing, since we already have the stiffeners riveted on. I dont really want a bunch of extra holes in the webs? For the oubaord ribs could we use the stiffiners as "flanges" for the ribs , then just rivet new stiffeners on in bettwen the ribs ?

I helped Vince Frazier with plans reworking. Check with him for the drawings, but I don't recall any of this being a problem. We did end up reversing the bellcrank rib to.

Also on my fuse the #7 bulkhead is 24.25 wide and my turtle deck formers from Harmon are 23.5 . the rest of the bulkheads are wider then the Tdeck formers also. I think i can "tweak " things and make it work,any thoughts here? sorry to pile on the questions ....Any help would be great! Thanks Dan Weseman
Click to expand...

Cut off the lower 4" or so of the upper #7 flanges (just above the top longerons), and re-flange it to fit the fuse dims. Another piece o cake!

Mark
 
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