13mm Competition Rocket Glider

[TheAviator]

I got a shiny new Nikon D3200. What better way to use it than document my first build of the year. (Graduate school takes a lot of time. Who'da thunk?) I'm still getting used to the camera, so bear with me.

I played around with my aircraft spreadsheet until I got a Reynolds number and stability margin I was comfortable with. The basic stats are as follows:

Glide Weight: 15g
Wing Area: 16.5 sq. in.
Engines : 1/4A3-3T, 1/2A3-2T, A3-4T

I'm using balsa from my stash of good contest grade balsa, so the wing uses 5.5 lb/ft^3 1/8" thick balsa. I'm also tissuing the flying surfaces using Peck Polymers domestic tissue and SIG nitrate dope. The spar will be a length of 1/8" square spruce from SIG.

For tissuing, I mix dope and thinner approximately 50/50 and brush a coat onto the surface I'm tissuing. I let this dry and sand with 220 then 400 grit sandpaper. I don't want to remove the coating, just smooth the surface and remove any protrusions. I cut a slightly oversized piece of tissue, lay it on the surface and brush thinned dope over until the tissue is saturated.

I've got the top of the wing covered and the tissue on the bottom is drying. I'll get some more pictures after I trim the bottom covering.

 

[TheAviator]

Got a little more done. Covered and trimmed the bottom of the wing and sealed the edges. Unfortunately, I'm going to have to cut this beauty up tomorrow.

 

[TheAviator]

Got some more done today. I sliced and diced the wing up into three pieces and reglued with the requisite dihedral angle. The low aspect ratio of this glider demands a slightly higher than standard dihedral angle, so that's why it looks a little weird. I also got a decent start on the fuselage, cutting out the boom, pylon, slide rail, and motor tube. So far, the mass budget is:

Wing: 2.9g before sanding, 1.9g before tissue, 2.9g after tissue
Fuselage with slide: 3.7g
Empty 1/2A3-2T Casing: 3.5g
TOTAL: 10.1g

I have 4.9g left for everything else, so I'm expecting to come in right on target or a little under. We'll see what happens.

 

[TheAviator]

Almost done! I can't seem to find my stash of BT5 nose cones, so I'll search around an find something. Mass with engine so far is 10.8g. Only 0.7g for the tail surfaces! Balsa wood is an amazing material.

 

[majordude]

Nice job!

I'm thinking tissuing it is overkill. I used to tissue C and D for added strength but the smaller birds won events stark naked! All I typically did was use a 1" wide Sharpie and "paint" the underside of the wings black so the timers could see it better.

 

[gdjsky01]

Very nice work!
- J

 

[TheAviator]

Nice job!

I'm thinking tissuing it is overkill. I used to tissue C and D for added strength but the smaller birds won events stark naked! All I typically did was use a 1" wide Sharpie and "paint" the underside of the wings black so the timers could see it better.

Tissuing might be overkill, but I am using super lightweight balsa. I also plan to eventually piston launch this on A3-4T's, so the tissuing might be a good idea there. It's got very little wing area, so a full A boost will get it going very fast.

Also, I really like the color and texture of the tissue.

 

[majordude]

A3-4T? Not A3-2T?

It's been so long since I built one I have no idea.

 

[TheAviator]

A3-4T? Not A3-2T?

It's been so long since I built one I have no idea.

No such thing any longer. Can't say that I've ever seen an A3-2T, and while I most certainly haven't been alive for as long as you've been flying rockets, I have been doing this for some time.

 

[majordude]

Really? No A3-2T? WOW.

And I think Estes used to make an A3-6T(?)... 4T sounds too short for PD or SD competitions. :-(

I just got back into rocketry about 6 weeks ago after having been away for 13+ years. I'm happy that CTI has entered the hobby but saddened that Estes has cut a lot of their better (IMHO) engines. :-(

And I didn't mean to offend you (if I did).

Like you, I love competition rocketry and it simply doesn't exist in SoCal. Frankly, that's why I left the hobby in 1999 (or thereabouts). You can only fly sport so long before it becomes repetitive.

 

[TheAviator]

No offense taken; the last statement was supposed to be somewhat tongue-in-cheek. Guess sarcasm doesn't come across too well over the interwebs.

I would love to have the -0, -2, and -6 delays in the A3 series, but they just aren't made. Maybe if we pester John Boren enough, they'll bring back the -2. At least Estes brought back the entire C11 line and the A10-0.

You should shoot Ryan Coleman an email. He's my West Coast counterpart. (I'm the Northeast Region Contest Board Chair.) Check the Pinkbook contest directory. We're always looking for new contest directors.

 

[majordude]

It's very discouraging. DART used to fly competitions but their calendar suggests that they have given up. I think SCRA did the same but nada as well. Sigh.

 

[cjp]

Very nice build Brian.Are you bringing it to this weeks launch?I the school in Chagrin Falls has a very small field.They're also a launch in Amherst with the Skybusters club.Don't know if I'm going this week as I was thinking of putting in my garden Saturday.

 

[TheAviator]

Very nice build Brian.Are you bringing it to this weeks launch?I the school in Chagrin Falls has a very small field.They're also a launch in Amherst with the Skybusters club.Don't know if I'm going this week as I was thinking of putting in my garden Saturday.

It will be flying in Pittsburgh this weekend at the Steel City Smoke Trail regional. I will unfortunately not be there because I have "practice" for my graduation from CWRU on Saturday. I'll make a report on how it goes.

 

[cjp]

First let me offer my congratulations!Looking at my last post,I don't think I should post when I'm tired.I had just got back from a long ride on my mountain bike and was not thinking correctly.I have my Ecee glider ready to launch and if the weather delays it to Sunday, I might get a chance to fly it.

 

[kjohnson]

Sean flew this glider really well today. Very high boosts and he picked good air.
kj

 

[TheAviator]

Sean says he farts better air than he can pick. I tend to agree with him. He just got lucky.

Launch report:

Flight 1: sticky piston 40s
Flight 2: good piston, good air, 102s and a new NAR 1/2A-RG team record.

 

[Buzzard]

Congradulations on the new team record. I had set the previous team record of 99 seconds in Herne, TX June 22, 2003 for the Pod Bay Doors, T-201. A slidewing that was flown without a piston. I was ready to make the first flight when James Duffy quietly waved me and then gave me the green light. Duffy can pick air.

What are you flying for ARG at NARAM?

Chas
Going home to Ohio for N55

 

[TheAviator]

Not sure yet. I may test this design on an A for visibility. I'm afraid that it'll get too far away for the timers to see.

 

[TheAviator]

My brother hacked a nosecone on for the competition, so I removed it and added a proper one with string hooks and epoxy protection. Here's the actually finally finished product. Weighs 12.7g with an empty 13mm casing.

 

[JPVegh]

Congrats on a successful design and a great time. Great job man!