Author Topic: DE (Cabin Mod) tail Modifications (Read 21250 times)

rfeenstra · « **on:** March 22, 2017, 10:13:21 PM »

A few of you were interested in the modifications to my DE that I proposed a couple of months ago. Well, those mods are well under way. When I built my DE, I added a cabin which extended the wing span by some 32". I seriously considered extending the tail but chose to build per plans. I moved the firewall back by 5" to help compensate for the heavier A65 I was going to put on the nose. CG wound up at the recommended 25% MAC, which proved to be too far forward as I needed a bit of throttle to flare. I added 10 lbs. of lead to the tail and a 3 lb heavier tail wheel bringing the CG back to about 29% MAC. A dead stick landing proved that I could flare w/o engine carrying almost no extra speed. I decided to extend the tail to help get rid of the lead. So, I cut off the tail just behind the cabin and built an new tail and tail feathers. Given the additional moment arm, I reduced the size of the tail to help compensate for the additional steel tubing needed for the additional length. Here are the results so far.

The old tail weighed 23.4 lbs. The calculated weight of the new tail (tubing length times weight/ft. plus welding rod and fittings) is 29.5 lbs., 6.1 lbs more. The new tail has an integral fin and that is included in the weight.

The old stab, elevator, rudder, and fin weigh 25.2 lbs. The new stab, elevator and rudder weigh 19.2 lbs. So, so far I'm about even with the weight of the tail feathers 26" farther back.

I decided to streamline the fuse dramatically, so I added formers and stringers to give the fuse shape similar to a Champ. I estimate that the weight of all the wood will be in the neighborhood of 10 lbs. When I disassemble for painting, I will weigh. All said and done, I may not actually loose weight getting rid of the lead, but at least the weight will serve a useful purpose. I flew this bird for some 3 summers. I was getting bored! Part of the fun in these projects is the initial build, and then contemplating, fulfilling, and testing modifications help keep the project interesting. One can fly over the same territory slowly for only so long before boredom sets in!

Attached is a picture of the old tail (perhaps a wind sock pedestal?), and a few pics of the the new tail and tail feathers. In the background you will see a bit of a 7GC which served as a model for the new tail.

Dan_ · « **Reply #1 on:** March 23, 2017, 08:42:27 AM »

Awesome mods. Chief Eagle..!

ArcticDave · « **Reply #2 on:** March 23, 2017, 11:47:37 AM »

Looks great! Those formers are awesome. That will look really good when covered.

MrG · « **Reply #3 on:** March 23, 2017, 01:31:28 PM »

Well have to say thats better than i thought it would turn out - agree on the emp mods too

rfeenstra · « **Reply #4 on:** March 23, 2017, 02:31:31 PM »

Chief Eagle. Hmmm. I like that!

Dave Stroud · « **Reply #5 on:** March 23, 2017, 06:51:51 PM »

Very nice progress. An inspiration for sure. Could you please share the dimension from the aft wing strut attach point on the fuselage up to the bottom of the aft center wing part near the rear spar ? Would a 5' 10" or 11" fella fit in there ok ? Please keep pics and description of your mods as thing develop . Thanks.

rfeenstra · « **Reply #6 on:** March 23, 2017, 07:08:02 PM »

Dave, I can try to measure that. i built the cabin so my head is not under the wing. I used the dimension given in the plans. Without the bottom of the wing over my head, I have excessive head room (I'm 5' 10''). I actually considered lowering the wing by a couple of inches, but decided that would be way to much work as lift struts, fuel lines and who know what else would also have to be changed. A 6' person would have no problem getting in or sitting in my plane.

rfeenstra · « **Reply #7 on:** April 24, 2017, 06:36:36 AM »

Progress. Top covered, bottom is next. Control surfaces are covered, stitched and taped.

rfeenstra · « **Reply #8 on:** April 24, 2017, 07:06:45 PM »

A lot of progress since I posted the last pics. Couldn't resist putting the tail feathers on to see what it would look like. Still have a lot of taping to do, but getting close to the painting job. Don't like painting! Maybe I'll be flying again in a month or so. Then again, maybe I'll make doors which will delay me another month.

stevejahr · « **Reply #9 on:** April 25, 2017, 03:29:33 PM »

That looks like a proper little airplane

rfeenstra · « **Reply #10 on:** May 14, 2017, 06:13:56 PM »

painting has begun! First cross coat of color. Same color as before as I need to match the wings. I may reduce the number of coats to save weight, leading to a slightly different shade of yellow. But then, there were many shades to start with! Yellow does not cover well and the depth of color gets better with every coat. But it adds up weight-wise.