HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 09, 2013, 11:51 AM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,207 Posts
Question
Ballast a Wing? How to do it?

I have a Weasel and a used Chevron that I think is a Wing Warrior. I was out in something like mid-teens to 30 yesterday with both. I had full ballast in the Weasel and it flew like a Weasel...great.

Switched over to the 48" WW. I had just put a new battery in it and recovered part of the center. Generally it's in decent shape. It took a couple clicks of reflex to trim and then flew like it always does, It's kind of a dog, at least compared to the Weasel. It's slower, less maneuverable (no surprise there), and actually seems to get kicked around more in the gusts. The only think it has going for it is size for seeing it at distance and yesterday's conditions would not allow this anyway. I wouldn't do much except roll it occasionally. It barely carries enough energy to do a very sloppy loop. It's an oft recommended combat wing and it seems like it should fly better. Maybe I'm spoiled by the Weasel?

I tried taping some lead on the front leading edge. In a blind test I'm not sure I could have told the difference. Flew about the same and did not need any trim to compensate.

How do you ballast a wing?
Make a hatch at the CG to put lead in? Insert a hollow spar when building for inserting ballast? Does it make any difference? Does it entirely depend on THE delta being flown?

My buddy also has a WW and he taped a mess of lead on the front. I'm not sure that made much real difference.

The Weasel has a hollow spare right on the CG and I simply slide a steel rod into that. For less ballast I tape bits of lead in the throw hole, also at the CG.
Ballast settles the Weasel right down.
flydiver is offline Find More Posts by flydiver
Last edited by flydiver; Jun 11, 2013 at 10:15 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 09, 2013, 05:40 PM
Registered User
Ward Hagaman's Avatar
San Diego
Joined Mar 2003
2,284 Posts
I bought a big serving spoon from the grocery store and melted lead shot in it with a propane torch (outside) and it makes a nice teardrop shaped 6 ounce piece of ballast to tape on.

I wouldn't put the lead on the leading edge, it should be at the CG position, which for a Raider, for example is something like 8" from the LE.
Ward Hagaman is offline Find More Posts by Ward Hagaman
Reply With Quote
Old Jun 09, 2013, 05:55 PM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,207 Posts
Quote:
Originally Posted by Ward Hagaman View Post
I bought a big serving spoon from the grocery store and melted lead shot in it with a propane torch (outside) and it makes a nice teardrop shaped 6 ounce piece of ballast to tape on.

I wouldn't put the lead on the leading edge, it should be at the CG position, which for a Raider, for example is something like 8" from the LE.
That's what I figured on positioning. I was surprised that a noticeable change in CG position weight (4" of 1/4" pencil lead) didn't affect trim or flying characteristics that I could tell. I did bend it around the tip and tried to feather it into the foil with tape.

Interesting idea in streamlining ballast. (Lead fumes are toxic!)
Top or bottom? Top I would guess.
flydiver is offline Find More Posts by flydiver
Reply With Quote
Old Jun 09, 2013, 07:52 PM
Flagstaff, AZ
dawsonh's Avatar
USA, AZ, Flagstaff
Joined Mar 2003
3,828 Posts
First a little semantics... a "Delta" wing has a more triangular wing... not a great shape for slope gliders. The Weasel could be considered a Delta wing; but is more accurately a described as a "plank." Most combat wings, like the "Wing Warriors" are "Chevron" wings.

Does ballast add performance on windy days? Generally yes... especially if you have a clean, well balanced ship. The added weight should give you a faster terminal speed (especially if you "pump" it up) and as a result more momentum to push you through aerobatic maneuvers... like loops.

Ballast should always be placed at the CG. Spoon weights are nice and aerodynamic can be taped to the top or bottom of the wing. If your sparring is not in the way, you could build a small hatch to hold some weight.

Weasels are amazing gliders. They are super versatile and seem to fly great in light and moderately heavy air. The molded design makes it easy to setup the CG and to add ballast.

Wing Warriors are great flyers too. The Ridge Runner is fast and the Raider is a super aerobat. From your flight description, I think you need to tweak the CG on your WW. You may be (very) nose heavy... which kills your performance. You should not have much, if any, reflex in the elevons. If you are nose heavy you need lots of reflex to fly level. Reflex adds tons of drag and makes inverted flight more difficult.

The next time you go flying do some "dive tests." Trim you glider for level flight and then push into a 45° dive. Let go of the sticks and see what happens. If your glider pitches up, you are nose heavy. If it holds the 45 down line or just barely pulls out then you are near neutral. Try to fly your glider with a CG as close to neutral as you can. Fly inverted. If you have a neutral CG you will need very little push to hold the nose up.

If you push the CG back; reduce your elevator throws accordingly... since the elevator will become much more sensitive (powerful) at a more neutral CG.

Good luck.

Dawson
dawsonh is online now Find More Posts by dawsonh
Reply With Quote
Old Jun 09, 2013, 07:53 PM
Objects in mirror are losing
1000MPH's Avatar
USA, NV, Reno
Joined May 2003
3,566 Posts
Combat wings are not Delta wings. Most people here refer to them as Chevron wings. Now a Weasel I guess could be considered a Delta but most people consider it a plank.

Wing Warriors are excellent kits. If it flies like a dog you've built it poorly or haven't taken the time to set it up correctly.
For our purposes, the CG doesn't change with airspeed. Whatever type of ballast you add, you need to keep the CG per specs.
I'm also a big fan of spoon weights. They tend to eject themselves in crashes instead of destroying your plane from the inside out.
The weight should go on top and you should avoid any high negative G maneuvers, for obvious reasons. I like to use 2 weights in high winds and I place them along the CG outboard of the CL about 8-10”. This will help span load your wing and hopefully keep it from “taco-ing”.
1000MPH is offline Find More Posts by 1000MPH
RCG Plus Member
Old Jun 09, 2013, 07:55 PM
Objects in mirror are losing
1000MPH's Avatar
USA, NV, Reno
Joined May 2003
3,566 Posts
Err, what Dawson said.
1000MPH is offline Find More Posts by 1000MPH
RCG Plus Member
Old Jun 09, 2013, 08:17 PM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,207 Posts
OK, Chevron not Delta, got it.
I don't think of the Weasel as a 'plank' but I can see that. To me, so far. planks stick straight out at 90*.

I have very little reflex as I see it, maybe 2-3*, and I've balanced it to spec at 8".
I didn't even think to do a dive test....duh. I would have done that with electric. Funny how a different setting will change your perspective.
I'll try that next time I go out. Maybe I'll make me some spoon weights.

Just to be defensive, I didn't build it, I got it used. But, I've had it awhile and it' doesn't look to be poorly built. Basic Chevron, covered in monocote, with balsa elevons. Covering is pretty decent, no warps, winglets just re-done in 2mm coroplast from the original template, straight and true. Nothing jumps out at me that says there is a problem with the build.
Having said that the ONLY other slope plane I have personally to compare this with is the Weasel ignoring my original Revert (plank) I learned on. My buddy was flying a Xeno in slope form (no power) yesterday at the same time and that looked to be flying better but I didn't do any stick time on it.
flydiver is offline Find More Posts by flydiver
Last edited by flydiver; Jun 09, 2013 at 08:30 PM.
Reply With Quote
Old Jun 10, 2013, 12:02 AM
Registered User
Ward Hagaman's Avatar
San Diego
Joined Mar 2003
2,284 Posts
I would play around with the CG just in case. A stick-on weight can tell you a lot in a few short flights...many plane manufacturers publish very conservative CG locations.
Ward Hagaman is offline Find More Posts by Ward Hagaman
Reply With Quote
Old Jun 10, 2013, 12:06 AM
Registered User
cityevader's Avatar
United States, CA, San Jose
Joined Mar 2012
2,731 Posts
I keep on pushing the inverted flight test (particularly for the Weasel) as it'll immediately determine if the cg is fore or aft ideal. Ideal is hardly ever ever where spec is. Spec may be flyable and some may be good, but "best" is where the plane wants it. I balance to spec, and reduce nose weight until it flies inverted with hardly-to-no down elevator input needed.
In my case, approx 3/16" behind the rearmost edge of the factory CG dimple.
Two weekends ago my buddy and I swapped transmitters mid-flight and his nose-heavy Weasel was sloppy and he noted how crisp mine was, except for the rates' programming (Approx 8th flight from maiden of my Weasel and dialing in the CG and alternating throw adjust/cg adjust).

If it dives to the earth when inverted get the lead out of the nose!!

Edited to reinforce: ANY plane, once properly balanced, is a whole 'nuther plane entirely. Bad behaviors become dream-like. It's so easy to not understand what your plane is doing. Since the late-80's I've never really known how to balance a plane, and now that I know, my eyes are opened.
Just like my mountain biking passion,and never really knowing how to jump a friggin' jump. Once it was taught in a fashion I could understand, I was literally jumping doubles of 6' high 15' gap within a couple weeks. Every stinking obstacle I'd ever passed up before made the countless different trails new and exciting. Every single trail was re-ridden many times with a new joy I can only equate to making a dog of an airplane turn into a dream.
cityevader is offline Find More Posts by cityevader
Last edited by cityevader; Jun 10, 2013 at 12:14 AM.
Reply With Quote
Old Jun 10, 2013, 10:22 AM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,207 Posts
Quote:
Originally Posted by cityevader View Post
In my case, approx 3/16" behind the rearmost edge of the factory CG dimple.
.
For the Weasel?
I would think that far back CG would start to get floaty and stall prone with poor penetration. Obviously have not tried that. I use the Weasel at the recommended CG. It's one plane that seems to be set up remarkably well. Other planes I don't believe the CG and start working it back also.

I only get maybe a half dozen slope opportunities a year. The only hill locally is a small 45 foot pimple of a hill that only functions in winter storm weather...sometimes. Too little wind, no lift. Too much wind, lift is blown down. Often I have both conditions in the space of a minute.
Generally one or 2 days have 'good' wind, non-gusty with nice lift. Gusty conditions make sorting out fine points in the plane somewhat problematic. The last outing was mid-teens > 30mph, but I could tell I wasn't happy with the way the WW flew while I was fine with the Weasel.
flydiver is offline Find More Posts by flydiver
Reply With Quote
Old Jun 10, 2013, 12:01 PM
Registered User
cityevader's Avatar
United States, CA, San Jose
Joined Mar 2012
2,731 Posts
Don't just start out with an aft CG! move it back incrementally and observe the plane each time (and at some point elevator throw will have to be reduced as the tail becomes more effective)

Stall prone?! That's a sign of nose-heavy, actually.
With the CG where the plane actually wants it (versus the "safe starting point" of a manufacture's) gives a fabulous stall characteristic. In fact, one can continually speed a plane down with steadily increasing up elevator until the plane just sits there. Even the ailerons are effective at that low speed. When it does "stall" it doesn't need ANY altitude to recover, merely a reduction of all that up elevator gets it back to flying. (Granted, I'm referring to while slope flying). A nose heavy plane, upon feeding in increasing up elevator will prolly drop a wing hard, or at a minimum, stall hard and dive quite a bit until airspeed builds again.

Flip that Weasel upside down and if it dives, get the lead out!

Oh yeah, the original question of ballast. I lined the finger hole with foil, carefully removed it and poured molten lead and got a 4oz weight that merely needs to be taped in. (sucks losing the finger hole tho). All my other planes get weight taped on top at the CG.
cityevader is offline Find More Posts by cityevader
Reply With Quote
Old Jun 10, 2013, 12:05 PM
Registered User
flydiver's Avatar
United States, WA, Seattle
Joined Jan 2007
5,207 Posts
It does dive. I need maybe 10% up stick to hold it. I'll certainly play with that next outing.

Same with the Wing Warrior?
flydiver is offline Find More Posts by flydiver
Reply With Quote
Old Jun 10, 2013, 12:09 PM
Registered User
cityevader's Avatar
United States, CA, San Jose
Joined Mar 2012
2,731 Posts
just remember, esp with flying wings. small weight adjustments only. I have a 1/4 oz flat wheel weight taped to top between Weasel's nose and wing and will move it around within a one inch range to play around with CG within a flying session (I rarely leave things well enough alone!)
cityevader is offline Find More Posts by cityevader
Reply With Quote
Old Jun 10, 2013, 07:54 PM
Confirmed Chronic
screamin' eagle's Avatar
Pacific Palisades, CA
Joined Jul 2004
9,216 Posts
Most every sloper I've ever owned needed a few flights, if not a half dozen, to tune optimally. You fly it at different slopes, in different conditions, first messing with CG and then rates. I'll spend some time dialing frontside rates, and then DS rates. You just can't set the CG on a plane, no matter where it is, and assume it's optimal without experimenting a bit.
screamin' eagle is offline Find More Posts by screamin' eagle
Reply With Quote
Old Jun 10, 2013, 11:43 PM
Registered User
cityevader's Avatar
United States, CA, San Jose
Joined Mar 2012
2,731 Posts
Yup. A solid 8 flights to tune my Weasel. But it truly is ever changing. Some folks think I'm wacko when I talk about different CG for different conditions. Wind blowing more directly from underneath vs not so much vs true thermal mode with no wind, and it takes some fiddling. usually a 1/4" or so of movement with the 1/4 oz weight(more for a larger bird). Only a couple of brief flights is all. Think of it as stretching before a sport, just launch/land/trim to work out the kinks.
Some guys can only follow a concise formula on a piece of paper to set up a plane and never deviate. Nothing "wrong" with that... but that's like trying to wakeboard with a snowboard (very poor analogy). It can certainly work, but it'd take an awful lot of extra work! Flying a balanced plane takes so much less effort and allows for more exploration of what plane/pilot can do.

I'm constantly fiddling because it matters so much. A toss/land/trim, toss/land/trim, and final toss and it's good to go.
cityevader is offline Find More Posts by cityevader
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How to find CG on a Delta wing? mikes68charger Scratchbuilt EDFs 33 Apr 24, 2014 02:10 PM
Help! How to secure ballast tube & ballast? FRIDAY_2008 Sailplane Talk 2 Feb 11, 2013 05:36 PM
Discussion How to glue lead ballast ?? headon Slope 15 Jan 31, 2013 08:25 PM
How to ballast? toygeek Slope 20 Mar 31, 2004 12:11 PM
How to ballast DLG? ferradas Hand Launch 8 May 19, 2003 12:37 AM