burkefj's blog View Details
Archive for January, 2017
Posted by burkefj | Jan 29, 2017 @ 12:24 PM | 8,929 Views
I've been thinking about this one for a while, but didn't think I could get something flyable with the small wing the Pegasus launch vehicle has, and with the weights of components. However my recent learnings with my Mace I thought I could get something done under 11 oz with maybe a passable look and glide.

So, I scaled the wing up of course, took a crack at boost CG and moved things around in openrocket and my rc cg programs and decided on placement of components. The wing sits on sort of a platform, so I faked that with some little extensions in front and rear of the wing, with some reinforcing gussets below. Idea was to look like pegasus but be light. There seems to be a number of tail shapes and configurations in the photos I've seen, I chose one with a horizontal stab so it would match what I'm doing for the controls. Most of the photos show the fins at 120 degrees to each other, but the ones flown off of the B-52 I found were at 90 degrees to the vertical stab. Wing area is right at 1 sq foot.

Came in right at 10.75 oz, first test flight was a tiny bit pitchy on boost, but glide was much better than expected. I added 5 grams to the nose and it was very stable on boost, with a very decent glide, landing speed is faster than my others due simply to the wing loading but the drag is fairly low.

Working with Stickershock23 to do the rest of the markings.

38" long, 22" wingspan, BT-80 lightweight tubing from bms.

Here are three flights from this...Continue Reading
Posted by burkefj | Jan 23, 2017 @ 09:29 PM | 8,354 Views
I've wanted to do an RC RG similar to a Mace Missile. The Mace used spoilers, not ailerons for roll and a high V t-tail for pitch. I was worried about stiffness and tail weight for a true T-tail, so wound up doing a mashup between the Mace wings, with alcm full flying surfaces and a stub T-tail to give it a mace-like look. I used black vinyl to simulate the engine intake on the bottom, as well as to shadow the tail to give a bit of a boat tail look when viewed from the side. Later Mace missiles had a dog-house or a shroud over the top rear to stiffen the tail so it wasn't a true boat tail anyway. I also built up a version with an ALCM engine intake on the top with the vertical tail, and moved the wing back an inch to remove the need for any nose weight. I haven't finished the alcm version, but the Mace came out at just under 12 ounces and flies very nicely. Diameter is 2.6" and length 38", wingspan 28.5" for both. The alcm version should be closer to 11.25 oz rtf due to the wing/CG movement.

RC Mace Missile rocket glider flight (1 min 24 sec)

Posted by burkefj | Jan 10, 2017 @ 01:06 AM | 10,172 Views
I've wanted to try doing a full fuse RC rocket glider Mig 21 ever since I built a profile version a few years ago. I settled on using the same vertical stab/wing/tail of the profile and use a 2.6" bt-80 lightweight tubing I had. I found a used nose cone I had and chopped off the nose and trimmed about 3" off of that keeping just the tip. I then glued in a piece of 6mm depron to block the rear of the nose cone and glued the tip onto that to give the characteristic mig 21 look. A 28" long tube seemed about right for the body and I decided on a sort 12mm sandwich profile for the canopy and spine to reduce drag instead of a full turtledeck.

I used a rocketry program called openrocket to build a mass model putting in the weights of the components including electronics, tubing, depron etc, with an estimate of my required boost CG and what nose weight might be needed. It looked like one ounce of nose weight would do the trick and keep me at 12 oz rtf using a 24mm E-6 rocket motor which will boost that weight to around 500'. Wing area at just over 1 sq foot is about half of my other rc rocket gliders so glide will be steeper, but not as steep as my bomarc which weighs closer to 14 ounces rtf with a similar wing and much more draggy design.

I decided to use the tab for the vertical stab that goes through the body tube to hold the motor mount in place, and to use full flying tail surfaces since that was very easy to do by putting a simple aluminum pivot tube...Continue Reading