Discussion in 'Rocket Boosted Gliders' started by burkefj, Nov 3, 2014.
Here are some liftoff/flight shots on both the H-97 flight and the H-115 Dark Matter flight
OMG...too cool for school
Yeah, what rstaff3 said....
...and he even got a photo on Sport Rocketry!
Is there a new issue out that I haven't gotten yet?
Got a new one today.
You are right, there I am in all my glory
Here is a great series of liftoff photos that I got from Dave King this weekend, enjoy!
It was really windy for the flight this weekend, the pad and the locating pin at the base that locks into the standoff did their job and kept the model from rotating, but I had to stand out there and hold the rail since it was actually bending under the wind load with the rocket mounted...until the wind dropped and I was able to let go and clear just before flight. I've since put the locating pins on all my foam rockets since they are so light the wind can blow them around and I was afraid the twisting might pull the rail buttons out of the mountings. I also applied full elevator after burnout which kept the nose up till ejection, but I put my glider battery in the wrong spot so my trim was off for glide, took me a few second to fix it so my glider flight was shorter than it should have been.
Had my fifth flight this last weekend in the Tri-cities area in Washington. I pulled full up elevon during boost and it stayed vertical with no arc over, actually tail slid slightly before glider ejection, nice glide and landing with no damage. I'm amazed it has lasted a full season Actually, all of my large foam structure rockets are still going strong after a season with 5-8 flights on them from H-128's to I-205's, of course a little foam crunching here and there depending on how they landed or what they landed on, but easily repaired...
A terrific project and the photo's of the Titan and X-20 look great!
I decided against trying to do an airstart after release, tho total stack weight was getting heavy and it works so well as it is.
Its just keeps getting better....
Congratulations on getting this printed in the Jan/Feb issue of Sport Rocketry Frank! :clap:
Cool, I haven't gotten mine yet, so haven't seen it.
I read the article tonight. I thought it was well written and the information was easy to absorb. I enjoyed it very much. Congratulations, Frank!
Nice pictures and a great article, congrats Frank.
Thanks all, there were a few typos that didn't get caught by spell checker apparently....
After reading this thread, studying the construction, and seeing it was launched on a Dark Matter motor...
I am WAY overthinking the fins on my 10" paper project!!!
I would have -never- guessed a two ply fin with one carbon rod would be so strong.
I'm throwing out my bar napkins now
Did you do anything to seal the edges when you laminated your fins?
And, presumably, your CF rod was epoxied directly to a CR?
ThirstyBarbarian and I are wanting to plagiarize your idea, but need more information
No, I did not seal the edges with anything, they are just sanded smooth foam. The carbon fiber rod is set into a groove I made in each half of the fin groove then I used foam safe CA+ to glue the rod into one half and then 3m-77 spray contact cement to laminate the other half of the fin over the first half and rod. The fins are glued into a fin box on this model using a very small amount of epoxy on the fin root and CA+ in the slot. The fin box is built using CA+ and foam, the fin box takes the load, the glue on the fin is just to keep it from falling out. On the fins where I angled the carbon rod to the tip, again I'm not epoxying the rod to a centering ring.
Had two flights on Friday, perfect weather, just a bit of headwind. Was able to steer the stack so it stayed vertical right to ejection.
Looks like a fun combo. I bet the camera on the X-20 really changed the flight characteristics.
Not really, it's a keychain camera so small, it was a bit ahead of the cg so I put in a bit more up trim than normal but overdid it so it porpoised a bit on the first flight before I adjusted, the recording I included was the second flight after I readjusted the settings. On both of these flights I held full up pitch, down elevator on the video, early instead of just reacting as it arced over as on previous flighs and was able to keep the stack vertical for ejetion.
Ahhh, So you learned from the past that up elevator was what's needed to keep things straight? I was like holee molee, is he holding full elevator? But......... If that's what it takes, that's what is takes. Kurt
I did have a good headwind which would have made it arc more than normal, so held full elevator, It will boost pretty straight without any input, but after burnout it arcs over quickly, holding the elevator kept it dead straight to a backslide at ejection with no arcing over. I also think that due to being over stable, around 2 diameters, that the elevator isn't really having as much impact as I thought it would and so you need a lot.
So, by up-elevator you mean pitching the X-20 nose up? So, the up-elevator was for the most part pretty constant during the entire ascent and accounted for the wind? This is all pretty cool. Are you concerned about flying the X-20 into the wind on the glide phase or is this not too important?
I'm pitching the nose up relative to the top of the glider, when it is on the stack it acts like a canard so down elevator will pitch the nose up. I try to boost with the bottom into the wind, and glide into the wind, but sometimes the flight line is up wind and I dont want it arcing toward the crowd.
When I fly the glider by itself I note that it also needs some up pitch for vertical boost so I think the angled flat plates that make up the shape tend to act like a wedge and push it toward the belly, that might be another reason the stack wants to arc that way.
I think this makes six flights in the past year. Minor fin crunch/repairs depending on what the booster lands on and how the fins hit but no structural problems, just a bit of CA here for cracks and a few patches of foam if it was compressed.
My Titan has flown a bunch and the skin had a bit of dings etc from handling and flight, so I decided to cover the upper part of the body with silver monokote following the George Gassaway drawing, it will give a bit of protection from dirt and dings as well. I didn't cover the fins in silver yet, they tend to get a bit more scars than the rest of the model. I also glued in two carbon rods into the base plate and mounted two nozzles made from measuring jiggers using some heater hose and hose clamps, the idea is that they can flex when landing instead of transferring a lot of impact to the base plate.
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