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Old Feb 10, 2006, 10:35 AM
S.L.O.P.E.
howsthewind's Avatar
San Diego
Joined May 2005
3,464 Posts
Help!
Suggestions for building light weight

After a while being a "lurker"- reader and not poster I've decided to reach out! Hopefully, the questions I have aren't too embarrassing.

I've built a couple of planes, but they always come out on the heavy side. So I was hoping for some help.

I'm building another Raider any hints?
Like brands of strapping tape
Size of battery pack or other equipment
Should I use goop or epoxy or gorrilla glue?
Should I substitute different winglet material?
I've read about spackling, does that add lots of weight and why would I want to do it?
Other considerations?

I don't expect to do any serious combat, my buddy and I will probably run into each other every once in a while!

Thanks!
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Old Feb 10, 2006, 11:18 AM
Flagstaff, AZ
dawsonh's Avatar
USA, AZ, Flagstaff
Joined Mar 2003
3,830 Posts
A standard build should be fine. How heavy was your last build? I do a mostly standard build (I do bury my linkages and use Ultracote) and can hit 20 oz, just fine. I use Goop for the Spar and thinned Goop on LE, and tips... over and under the "Extream" strapping Tape. No spackle.

If you want a light "Raider"... get a Weasle.
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Old Feb 10, 2006, 11:28 AM
blah...
THUREN's Avatar
United States, OR, Bend
Joined Jun 2005
2,932 Posts
If the spars fit tight you can use CA to glue them in...

Pu glue mixed with a drop of water is WAY lighter than goop and almost as strong.

Only go "kinda" crazy with the strapping atpe in front of the CG...

move the servos and gear as far forward as possible...


All I can think of right now.....

Don
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Old Feb 10, 2006, 11:44 AM
The Predator
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Golden, Colorado
Joined Dec 2004
3,565 Posts
Welcome my fellow flier-
The question you pose turns out to be a very important and complicated one. The real key to building a nice tough yet light wing, in this case, is to know that wing and maintain a tight focus on it's CG!!! If you can hit the CG right off the work bench with out adding balancing weight you have done WELL!!! Here's how.
Generally I use fairly heavy building supplies to make wings that can survive just about anything and they still come out respectibly light weight using a lighter battery and focusing on keeping all the weight foreward to compensate for that lighter battery.
I used to be a Wing Warrior dealer so I know a bit about the Raider. Generally I have found the Raider to be fairly easy to build with light wing loading since it has such a huge surface area. But, they generally want to be tail heavy since they have ALL that surface area behind the CG.
If you really want to make a tough floater out of it here's what I would do:
Use a lighter NIMH 2/3s AA Battery about 700MA and push it up to about 2" from the nose, as far as you feel comfortable, laying it long wise with the wing span. Use either tough standard servos or some kind of mini metal gear servos and place them as far forward as you can while still maintaing a safe foam buffer at your leading edge, same deal. These moves are directed at getting as much weight foreward as possible to meet your CG while still using a light battery pack. Install the Rx behind the batteries with a 3/4" foam buffer between them to soften the poundings. Now, make a horizontal line across your wing span, perpendicular to the root, at the recomended CG. I believe 9 1/4" for a Raider.
Now just follow the strapping tape instructions and ONLY use the light weight mono directional strapping tape (what ever brand) behind your CG line and nice strong heavy duty 3m Bidirectional Extreme tape in front of the cg line. When you tape the triangle shape over the fore section of your wing let the tape strips wrap around the LE some to give that impact prone area more armor. Now use 2 strips of the Bi to wrap the Leading Edge. Let the LE strips of Bi over lap 1/2" along the very front edge of the LE so you have DOUBLE layer there where the big hits happen. Now at the front center section of your wing you have FOUR LAYERS of fiber tape right where the BIG HITTS happen and you just added a bunch of weight to the front of your wing allowing you to hight your CG despite using a light battery!!!. Now just do a light layer of thined goop on the entire leading edge and the nose section, on the tape only, to make it even tougher and the LIBERALLY DOUSE THE WHOLE WING WITH 3m super 77 and slap on your covering. Persoanlly, I use monocoat since it is tougher but, it is a touch heavier. Last, once covered and all ready to fly, I add one more Layer of thinned goop over the leading edge and that makes it SUPER tough and helps the covering from coming up and ripping up on those BIG DIGGERS!!!
Balance your wing temporarily to the recomended CG, fly it and try to bring the CG back as FAR as you can. Balancing is a whole other lesson. But the further back you can manage your CG the faster and more efficienly your wing will fly. Once balanced to your tastes THEN mark that CG. Make a tiny slit in the nose or tail (most likely the nose) and ad balancing weight until the wing balances where you maked your desired CG.
A light Raider will climb in the weakest of lift but top speed SUCKS. If you are having a good lift day and want to go faster simple tape on some lead weight right on you desired CG and it will fly faster. The Raider is Geneally SLOW compared to many. A hard hitter yes but that includes the gound and hard ground hits kill wings. I now deal Bees and I fly circles around the Raiders, plus the bees are tougher, longer lived, easier to build and I won the quite competitive Glacier ridge combat contest against several radiers with my Bee!!! Let me know what you think!!!
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Old Feb 10, 2006, 02:47 PM
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howsthewind's Avatar
San Diego
Joined May 2005
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Wow- thanks everyone for their responses I'll try and cover any outstanding items here-

My last build was several oz over the high side of the instructions- sorry but can't remember exactly- that plane has been rebuilt/repaired etc till it no longer resembles a Raider!

The CA for Spars and goop on the leading edge are ideas I never would have thought of!

I'll work this one with a lighter battery pack as recommended. Predator- what a detailed response! Unfortunately I've already got a Raider Kit, but I'll keep the Bee in mind for a future project! It sounds pretty killer. How do you "thin goop"? Are there any tricks for that? And any suggestions for where you can pick up supplies (specified Bi-directional tape, goop, thinning agent, etc.)?

My responses may be delayed- this thing called work keeps getting in the way!
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Old Feb 10, 2006, 04:55 PM
PNF
infopimp's Avatar
Los Gatos, CA
Joined May 2005
4,422 Posts
howsthewind:

Go to Advanced Search. Type in 'goop' as your keyword. Change the search to look only in titles. Go to the bottom and choose to see search results as threads. lastly, sort your results by "number of views, decending"

You will see at the top of the list, 3-5 key threads on gooping that will keep you entertained. Especially look for posts from daemon (ian) as he is the Goop Guru.

I'm gooping two Stembridge Thrusters right now... that reminds me, gotta go add another coat on my monster.
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Old Feb 10, 2006, 05:07 PM
dying to be flying
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Merced, CA
Joined Jun 2004
984 Posts
An alternative to gooping leading edge I like to wrap leading edge all the way around with 3/4" colored electrical tape. This covers overlap of top and bottom covering and protects reallly well. Keep all weight forward of center of gravity and you should be good as gold. I never use ca for anything, it becomes brittle and breaks on impacts. Use goop religously (my 2 cents).

Joe
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Old Feb 10, 2006, 05:28 PM
S.L.O.P.E.
howsthewind's Avatar
San Diego
Joined May 2005
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infopimp- Good call on the advanced search. I took a quick look and those threads should cover everything I needed to know about Goop... and then some!
Thraser- I hadn't thought about CA being brittle and I'll keep the electrical tape in mind. I've done it before with some success.
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Old Feb 10, 2006, 05:32 PM
Registered Lipo Abuser
Costa Mesa, CA
Joined Sep 2005
628 Posts
I just finished my superlight Raider. Instead of wrapping strapping tape across it, I put some carbon ribbon spars in it. By using a foam cutting tool, I made a slot 1 inch behind the LE, 1/4" deep. Put .09 x .25 flat carbon into the slot a ca'd it into place. I then ca'd .05 x .17 flat carbon onto the TE. By getting all of the strapping tape weight out of the tail, I could put in a 700 AAA nimh pack. The final weight is 16 oz taped up.

Was it more work than necessary? Absolutely. But it does create a super-light, super-stiff Raider and i like that.

Taylor
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Old Feb 10, 2006, 06:02 PM
dying to be flying
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Merced, CA
Joined Jun 2004
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howsthewind,

I'm sorry about the comment on ca, actually it's epoxy that is brittle. My mistake.

Joe
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Old Feb 10, 2006, 06:12 PM
The Predator
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Golden, Colorado
Joined Dec 2004
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I use the electrical tape too. It does work great for protection and holds covering seams down too, plus if you use a couple colors it looks down right sweet. Check out this Modified bat , the Com-bat and how I used the e-tape to sweetify it. I still use the thinned goop over that to maintain the sweet look after a couple rough days of flying.
Check out the "God God Batman" thread if you want to learn more about some of my sickest new creations, built for speed and battle!!!
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Old Feb 10, 2006, 06:26 PM
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Los Gatos, CA
Joined May 2005
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howsthewind - check your PM
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Old Feb 10, 2006, 07:59 PM
S.L.O.P.E.
howsthewind's Avatar
San Diego
Joined May 2005
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sounds like the Electrical tape is a winner. I'll incorporate it. infopimp thanks for the PM.

Taylor- I'm not quite that ambitious... yet, but do you have any pictures of the build? I was considering putting a little sliver of balsa on the TE, or am I know defeating the original light build desire?
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Old Feb 10, 2006, 09:52 PM
dying to be flying
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Merced, CA
Joined Jun 2004
984 Posts
howsthewind,
I am sure there are others more knowledgeable on this than I, but I believe that any weight added to trailing edge would have to be doubbled at the nose to compensate. Thus you defeat the light building technique.

Joe
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Old Feb 11, 2006, 12:31 PM
Registered Lipo Abuser
Costa Mesa, CA
Joined Sep 2005
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Quote:
Originally Posted by howsthewind
sounds like the Electrical tape is a winner. I'll incorporate it. infopimp thanks for the PM.

Taylor- I'm not quite that ambitious... yet, but do you have any pictures of the build? I was considering putting a little sliver of balsa on the TE, or am I know defeating the original light build desire?
No, sorry, I don't have a camera. It would have been perfect too because last night I stripped it and recovered it.

What would be the purpose of balsa? I put carbon in because 100% of the strapping tape used to stiffen the was behind the CG. While the carbon only came out a little lighter, the strengthing material is now in front of the CG. This allowed me to put in a battery that is 2.2 ounces lighter and remain at 9.5" CG. Plus it is stiffer. If your balsa is to stiffen the plane and remove some tape in the process, it might work. It depends on what size balsa you use. It might also snap. As thrasher pointed out, you need to add weight to balance the balsa. So in the end, it could make your plane stiffer, but not any lighter.

Taylor
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