McDonnell Douglas "Delta Clipper" Semi-Scale Build

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IIRC the nose is completely full of clay. On mine, the cord attachment point broke so I beefed it up. I lose a landing leg everytime. They are now pretty crooked :)

I do remember the nose being full of clay! IIRC, the landing legs departed mine on the first or second flight, and I never found them...
 
I'm going to unscrew the legs before each flight- they are 1/4" all thread rods, plus an epoxy/fender washer casting for each pad. They are adding some extra weight at the wrong end of the rocket, plus I guessed they may get bent on landing. The 1/4" polycarbonate fins should handle the landing. If not, I have constructed the mechanical fin attachment points so that I can replace a broken fin. I also drilled out the hardwood nosecone and filled it with epoxy/bb's and a threaded eye bolt to add nose weight. Heavy-duty kevlar shock cords throughout.

Mike Momenee
TRA#12439 L3
 
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The construction and finishing is basically completed. The rocket stands 56" tall. 18" at the base, and weighs 37 pounds without the Aerotech L1520 75mm motor. CG is at 28" thanks to a lot of nose-end weight. Clear polycarbonate fins still have the protective paper on them. My first attempt at fiberglassing a body- certainly not pretty, but hopefully effective. The second pic is of the avionics hatch, which will contain an apogee deployment altimeter and a timer as backup. Third photo is of the altimeter bay epoxied to the back of the hatch. Jolly Logic Chute Release for the 84" Fruity Chutes Ultra Iris Compact. SkyAngle Cert 3 Drogue chute, and piston deployment.

Still need to ground test for proper ejection charge load for the 3" Blue Tube internal tube. Spring launch at Three Oaks MI.

Mike Momenee
TRA #12430 L3

S
 
Cool. Maybe for the next one you could deploy the base panels like in the first photos of the real one. All that lovely base drag would stabilize it right up with out all the nose weight or non scale fins. Too much drag? Then grid fin it up? . . . Never too much base drag! Base drag is your friend! Just bullet proof the panels and use a bigger motor! That will solve those nasty stability issues. Just like the kid at our club who flies the soccer field: Trust in Thrust! Yep, that is right Mr. RSO! Even some light and strong legs with big landing pads would help too. Tell the RSO she's got legs and knows how to use them! That should help get a pad assignment. Right?

Maybe build one using a 1/2 inch or greater launch rod? Better looking?. . . No, that would be way too embarrassing carrying out such a thick rod to the pad; all the young folks would laugh real hard at an old dude carrying such a thick rod! I guess Rails Rule and Rods Drool! I still have to sneak out the 1/2" rod when no one is looking to launch my B 58 Hustler. Even harder than getting by the RSO table:)

I love the old Quest kit on a composite D. I CA'ed the legs in and now I can't seem to break them off.
 
Maybe you could build one of these with the motor recessed way up front, then rear eject like they do with the pyramid rockets. Motors up front and forget the fins, the way a rocket should be! Greatly reduce all that no good, stinking, performance robbing nose weight. Use the power to drag up the base and keep her stable, just like those silly spool rockets. A good way to use that level 2 case I have had laying around and finally move up to level 2. No, it won't work, no oddrocs for a level 2 cert! The TRA boys tell me to go read the book, keep the motor and fins at the back of the rocket where they should be!
 
When you say to recess the motor way up front, I hope you're not asking me to recess it in the motor tube and unleash the dreaded "Krushnik Effect"- lol. I did a research paper on that topic my junior year of high school, and was fortunate enough to be chosen as one of twenty to present their papers at the NASA research center in Cleveland back in the 70's. Memories- sigh.

Mike Momenee
TRA #12430 L3
 
I would think there would be enough internal space inside and at the bottom this oddroc to avoid Mr. Krushnik all together. Nice big open base - no traditional body tube. Could even put some venting in up front for some cool bypass and gas dynamic effects. I have flown motors way up in pyramid rockets with no problem. No long skinny motor/body tubes needed, just enough to hold the motor as high as possible. Don't make a secondary combustion chamber by recessing a motor up in a skinny tube, make it all nice and open in the back end. Get some big centering rings and make a big internal parachute tube container, slide the motor mount up into it and rear eject that motor just like a nose cone, only backwards. The whole thing would come down nose first and the legs would be protected on landing. Could use one or two chutes, could be all together on a long cord or the motor mount could recover separately on it's own chute.

I know it is all just crazy talk. The RSO will tell me to go fly a 4FNC that recovers in a safe, traditional way. Rear ejection where the centering rings are not glued in - ridiculous! Big draggy panels or grid fins at the base just sucking all the power from your motor for stability - sacrilegious! Forward mounted motor acting like nose weight off a thick rod - silly! Motor ejection - no electronics - stone age!
 
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Got the Perfectflite Stratologger Altimeter set to fire the drogue charge at apogee, which will piston-push out both the 24" Cert 3 drogue chute, as well as the Fruity Chutes 84" Ultra Iris Compact, which is controlled by a Jolly Logic Chute Release set for 500 feet. As a backup, I have a Perfectflite MiniTimer4 with another ejection charge set to fire about 1 1/2 seconds after apogee, just in case something gets hung up in the3" dia.Blue Tube chute tube, or if the altimeter doesn't function correctly ("Belt & Suspenders").

The wires from the Pratt canisters will be threaded through a hole in the central body tube, where they enter into the avionics area inside the Delta Clipper access panel. Found a method for fishing the wires effectively and quickly. Just need to ground test a Pratt ejection canister to confirm 3 grams of 4F BP will do the trick- with the piston, probably quite easily.
Mike Momenee
TRA #12430 L3
 
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Ground-tested the ejection charge load. Used the Pratt Hobbies Variable Capacity Ejection Canister with 2.5 grams 4F BP. Chute tube is 3" dia. Blue Tube, 28" long with piston ejection. Had some old (2009?) Newton's Third canisters- they tested fine and used one as a backup. Both fired fine. I did learn that I had the Jolly Logic Chute Release tethered incorrectly (anchored at the quicklink connection with the shock cord and chute connection), and the 84" Ultra Iris Compact would have opened at ejection charge firing. Better to find out on the ground than during flight.

I had to use a 1/4" dia. wood insert to thread the ejection canister wires through the chute tube so that they can connect to the altimeter and the timer. I used some heat shrink tube, shirinking only half of it, and pulled the wires/shrink tube through the wood insert to hopefully seal the electronics bay from any ejection gases. It worked as I had hoped. April launch at Midwest Blast 2 at Thee Oaks MI.

Mike Momenee
TRA #12430 L3
 
View attachment 312463View attachment 312464

Ground-tested the ejection charge load. Used the Pratt Hobbies Variable Capacity Ejection Canister with 2.5 grams 4F BP. Chute tube is 3" dia. Blue Tube, 28" long with piston ejection. Had some old (2009?) Newton's Third canisters- they tested fine and used one as a backup. Both fired fine. I did learn that I had the Jolly Logic Chute Release tethered incorrectly (anchored at the quicklink connection with the shock cord and chute connection), and the 84" Ultra Iris Compact would have opened at ejection charge firing. Better to find out on the ground than during flight.

I had to use a 1/4" dia. wood insert to thread the ejection canister wires through the chute tube so that they can connect to the altimeter and the timer. I used some heat shrink tube, shirinking only half of it, and pulled the wires/shrink tube through the wood insert to hopefully seal the electronics bay from any ejection gases. It worked as I had hoped. April launch at Midwest Blast 2 at Thee Oaks MI.

Mike Momenee
TRA #12430 L3

Oh sweet! That'll b my first launch of the year, do you know which day you plan yet?
 
Quest Rockets sold a kit that flew on C6-3s. I really liked mine. Had 2 oz. of nose weight and no fins. Great flier, but it needs higher impulse motors. Have you thought about how you are going to put it on the launch pad?

I still have mine. I like to fly it on Aerotech D-21's.
 
Planning to launch on Saturday around noon, with Sunday as the fall-back day in case of inclement weather. About a three hour drive each way for us, so a noon launch is realistic.

Mike Momenee
TRA #12430 L3
 
The Midwest Blast 2 launch is on, and I now plan to launch the Delta Clipper on Sunday around noon. Lots of "firsts" on this rocket for me regarding its construction, and I hope to bring it down in one piece. Aerotech L1520 Blue Thunder motor and 45 pounds total weight.

Mike Momenee
TRA #12430 L3
IMG_3753.jpg
 
The Midwest Blast 2 launch is on, and I now plan to launch the Delta Clipper on Sunday around noon. Lots of "firsts" on this rocket for me regarding its construction, and I hope to bring it down in one piece. Aerotech L1520 Blue Thunder motor and 45 pounds total weight.

Mike Momenee
TRA #12430 L3
View attachment 317866

Woohoo, I'll be able to see this!! Going to be a premier flight
 
Successful launch on Sunday. 45 pound pyramid-shaped rocket achieved altitude of 1,535 feet on an Aerotech L1520 motor and drifted back safely on a Fruity Chutes 84" Ultra Iris Compact. Landed directly on one clear Lexan fin, but it simply flexed and bounced back to shape.

Here's a link to the Youtube video: [video=youtube;lzy7ij27ZHc]https://www.youtube.com/watch?v=lzy7ij27ZHc[/video]

View attachment 318493View attachment 318494
 
Awesome flight, really fun to witness it live, one of the premier flights of the weekend, great job!
 
Way to go Mike! I'm glad I had the pleasure of carrying that beast to the pad!
 
Thanks guys! And special thanks to noffie79, who helped me carry it to the pad, helped me set it up on the pad, and lugged it on his shoulder after recovery back to our rental van.

Whatever new project I may dream up in the future, it has to weight less than 20 pounds- this beast was awkwardly heavy!

Mike Momenee
TRA #12430 L3
 
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