TRF Summer Build Off: Delta Transport

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Amsterdam

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Joined
May 30, 2015
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Location
Bruce Michigan
I only have these sketches right now, I'll have to add RockSim stuff later.

once I'm building the booster design is bound to change. But I'm keeping the large tube fin for sure to hold the elevons flat

this is my first glider, trying to push myself for the contest.

edit: turns out I emailed myself screenshots image.jpgimage.jpgimage.jpg
 

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Yup! Forced me to grab an idea off the pile and just dive in.

I'm still quite new at this, no piles yet! I started drawing when Scotty dog asked if there was interest.

In fact this will be my first standard engine rocket I've made since returning to the hobby!
In my first year as a BAR I've made a bunch of mini engined stuff, a two staged big daddy, and a balsa sci-fi rocket that won't fly... It's too pretty lol

this rocket and a more stable two stage I've cooked up are pushing me to join a local NAR chapter. That won't be till they're finished though.

To the the build; I think starting with the glider and seeing if it shows any potential should be done first
I did a bit of work last night. CA'd the inside of the glider body, except for the last 1/4 inch or so where I glued a bt50 to bt5 centering ring with titebond , and epoxied in the cut bt50-bt20 transition.
Next pics will be the fully assembled glider, I cut out some of the balsa already, should have time later today to glue.

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Very cool design! I was just thinking yesterday that something like the Fat Cats F2H4 Banshee would be really cool as a contest entry...basically fins of different dimensions and designs in unique arrangements with a long stability probe added for launching. Making this a glider design as well is quite impressive! :)
 
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The gliders together!
It's 6.25" long with an almost 6.75" wingspan. I fit a centering ring at the front of the transition to help it ride off the booster at ejection. The wings are 3/32 balsa.

Spent a long time staring at it, thinking up a way to mount the adjustment screw and rubber band holders. I waited till the fin assembly was glued together to carve out a hole for the tiny dowel. If I make this again I'd either cut the holes prior to gluing, wait till it had a coat of sanding sealer ..or get better tools than a heavy gauge needle and a knife haha.
I filed the adjustment screw head down to a reasonable size, again if I were to make another I'd just buy smaller head screws online, nylon is TOUGH.


Glide testing:
*Prior to this I had no experience with gliders or airplanes so if you spot any crucial mistakes or have advice please share*

Right away I learned that gliders are real tricky to throw and a bad flight is more than likely the throws fault than the gliders. So I ignored all bad glides and only made real adjustments after decent glides.
I decided it needed more weight in the back. so I taped a lug filled with clay and a few bb's to the bottom aft of the body (3 grams of weight). This balanced out the glide and helped it's roll stability/ recovery. No more spiral death dives after a gust of wind, it would roll out of it and do a little pendulum swing before leveling.
I made the lug more permanent as you can see in the pics, I'm holding off stuffing it full of clay and bb's again till the gliders closer to its finished weight.


It's a tiny bit unnerving not knowing how much these ground level tests will reflect how it performs 300ft up but at least they show potential.
When there's more sanding sealer on the balsa I might chuck it off the roof a few times to get a better idea.


Once it's painted i think two strips of Mylar tape or chrome monokote for hinges should dress it up nicely.

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Very cool design! I was just thinking yesterday that something like the Fat Cats F2H4 Banshee would be really cool as a contest entry...basically fins of different dimensions and designs in unique arrangements with a long stability probe added for launching. Making this a glider design as well is quite impressive! :)

Thanks! That kit is crazy! Might have to buy or clone haha. Idk how necessary the probe is especially now that I've added a few grams of weight to that side of the body, but I really like the look.
 
Forgot a few pictures

the screw can fit flush inside the wing idk why that matters but it can

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Here's a shot with no elevator or screw.

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Started on the booster last night.

I made a quick decision to neck down to a bt-5 right at the end of the engine to leave more space for recovery. There's a lot of epoxy inside the tube and around the joints. Hope it will stand up against the pressure

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All Glued together.
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and it fits!
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The booster just needs fins, and I might have to come to terms with putting a small launch lug on the glider somewhere. I was hoping I could get away with mounting it only on the booster but it's pretty far below the center of gravity
 
Test fitting the giant ring fin/elevator stop, slotting tubes is a pain...I managed to slice my thumb pretty good. I'm taking the weekend off from this finicky build.

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Starting to look more like a rocket now!

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Thanks! That kit is crazy! Might have to buy or clone haha. Idk how necessary the probe is especially now that I've added a few grams of weight to that side of the body, but I really like the look.
Unless I'm misunderstanding this, the probe is completely necessary. Trimming a glider means placing its CG directly on top of the center of lift, which is the same thing as the center of pressure, or just a wee tad aft of it. Stabilizing a rocket means putting the CG well forward of the CP. So to go from boost to glide the configuration must change by one method or another, such as ejecting the booster with its forward probe.

Unless I'm misunderstanding your design and that's not the probe your talking about, in which case please disregard this entire post.

Edit: By the way, cool design. And you don't have to disregard that part.
 
Haha. Thanks jqavins

i think you've got the right probe. It was my idea to use it to balance out the placement of the gliders wing during boost. The probe, and its accompanying fin are attached to the booster not the glider. But as everything sits now I doubt ill use it.

I'll give some details on the design like I should of in the first place.
The glider is ejected, free from the slotted tube fin which kept the elevator shut during boost, and it rides up the booster body, over the nose cone and into the air.
With the glider ejected the boosters parachute which was packed under the gliders body is free to the air should open up.

boost
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Ejection
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Recovery
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thanks guys! Though I'd love to take credit for the "through the pod" method ..I can't. Rokitflites Fake-Wulf Is the only other rocket I've seen that uses it. Scratch or other wise.

i think I can take credit for the ring fin elevator stop though haha.

Right now I plan on making a few different styles of elevator to see if there's more performance to squeeze out of the glider,
I'm also thinking of using three smaller fins to attach the ring instead of the original idea of one small one large.
that large fin might catch the chute.
And of course put a launch lug somewhere.
 
i think I can take credit for the ring fin elevator stop though haha.
That is an inspired detail. The combination of that plus the way the glider deploys makes this whole design really cool.

Look forward to see some good video of his one, preferably with a zoom lens so we can see watch glider deployment.
 
Look forward to see some good video of his one, preferably with a zoom lens so we can see watch glider deployment.
Thanks! I only have an iPad to film with, I plan on taking it to a HUVARS picnic launch, it's about an hours drive but I was hoping someone there would at least be a forum member, if not armed with a decent camera and charitable spirit. i really don't know what to expect there, I've never been to a club/public launch so I choose one that's more in line with what I fly (lpr)
 
I'd definitely like to see this fly. If someone there has a newer phone that can shoot videos in 4K, you can zoom in quite a bit after the fact and still see clear.

Make sure you have a spotter for the glider in case it glides too well.
 
Uh-oh ....

Due to overhandling and moisture contact from tossing the glider around the glassine layer on part of the tube swelled, I attempted to lightly sand the area knowing the risk and wore the spot flaked and fuzzy.
Ah crap. I had this happen once before and I know that primer is NOT the thing use.. Worried it's only going to get worse the longer it sits I brushed a coat sanding sealer on the body tube. Maybes it's just the fumes talking but I think it worked.

EDIT: that worked incredibly well. DOPE ROCKS.

Almost didnt post this but I think mistakes and mishaps have there place in a build thread.
 
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Mistakes and mishaps on a scratch build? Nah...never happens! :wink:

Sorry to hear about that, but it sounds like it's fixable. The first launch of my spiral finned rocket somehow resulted in a prang on the mouth of the bt that was bad enough that I cut off 1.5".

For a few of my test rockets earlier this year I knew I was going to launch in wet conditions (snow), so i sprayed them with water proofing spray. I think I later painted them with spray paint and they were still fine YMMV.
 
Many people will tell you that the solution to fuzzies is thin CA, but I too have had good results with dope. CA spills are so much more dangerous and so much harder to clean up that I'll be sticking with dope.

We learn a lot from mishaps, and in my opinion build threads are as much about sharing what we've learned as about showing off what we've accomplished. So I completely and wholeheartedly agree that they should include the mishaps along with solutions.
 
Many people will tell you that the solution to fuzzies is thin CA, but I too have had good results with dope. CA spills are so much more dangerous and so much harder to clean up that I'll be sticking with dope.

this is my first build using dope, I'm probably dating myself here but I hadn't heard of the stuff till I did research on gliders. I can't see why it ever fell out of vogue, it's so easy to sand and gives a nice hard uniform surface.

I have some updates. The glider is in its final form and ready for paint.
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The only difference is the elevator I made 4 all together this one gave to best performance
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and a shot of the aft weight
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I don't expect it to be a contest flier haha, there's no dihedral angle to the wing, it's a little nose heavy too. at altitude I expect it to glide fast and twitchy.

EDIT: looking at the pictures and realized I forgot the sticking launch lugs, the plan is to attach two of them under the wing and one on the booster.
 
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I finally glued a launch lug to the glider. I stuck the first one on the lighter side, waited for it to dry and tossed it few times. The glide actually benefited from the extra drag on that side so I didn't bother with the other. I shot a light coat of primer and sanded a bit.
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glued two pylons to the booster, I chose 1/8th balsa for strength. Hopefully there'll be some extra drag stability too cause I don't plan on adding any extra finnage. It's pretty asymmetrical but it sims fine. The large ring fin seems to soak up any instability in the sims.
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the slots are so close! I'm just going to sand it till its perfect and add a strip of balsa to tighten up the fit. Like I did on the vertical slot.
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The rings not glued on yet
 
Love the design. I have the fake wulf Kit, after reading the instructions I have put it on hold until my skills catch up.
Something I am not quite getting. At apogee, what will make the glider slide off the front? I as thinking rear end eject would work (pod gets forcibly ejected out back with chute, either the jerk of the shock cord or chute opening pulls rocket body backward and inertia holds the glider in place.). Looks like your glider is covering the chute compartment (an idea I really like as you can choose a shock cord attachment that lets your rocket body descend horizontal--- awesome for damage free recover.). But I haven't figured out from your design what force gives the "jerk" needed to separate the glider.
 
Love the design. What force gives the "jerk" needed to separate the glider.

Thanks!

theres two huge holes in the bt-5 (sorry this is my best shot)
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The bt-20 fits over those holes
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And ejection gases are going to be channeled right into this centering ring
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I don't know if the fake-wulf works like this, but I have to assume it's similar.
The glider should go screaming off the booster lol

edit: does anyone know what an empty Estes standard casing weighs? I don't have one handy.. Hate to just waste one.
 
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