stunthanger.com
General control line discussion => Open Forum => Topic started by: John Lindberg on July 07, 2020, 11:19:29 AM
-
I need to make a sheet metal trim tab to place on the bottom of the wing on my "Blue Max", what thickness, metal type, should I use? Any suggestions? D>K
-
Copper is probably your best bet as it tends to be soft and bend easily. I suppose you can cut what ever size you need from the below.
https://www.amazon.com/X10-X-025-Copper-Sheet-Metal/dp/B00JWTF79O/ref=pd_lpo_60_t_1/137-0265080-9624675?_encoding=UTF8&pd_rd_i=B00JWTF79O&pd_rd_r=835c9814-b864-4979-a82b-995a38288fe8&pd_rd_w=42Xgz&pd_rd_wg=vCnT4&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=2M8DCS3M8XQMPVSA6SZY&psc=1&refRID=2M8DCS3M8XQMPVSA6SZY (https://www.amazon.com/X10-X-025-Copper-Sheet-Metal/dp/B00JWTF79O/ref=pd_lpo_60_t_1/137-0265080-9624675?_encoding=UTF8&pd_rd_i=B00JWTF79O&pd_rd_r=835c9814-b864-4979-a82b-995a38288fe8&pd_rd_w=42Xgz&pd_rd_wg=vCnT4&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=2M8DCS3M8XQMPVSA6SZY&psc=1&refRID=2M8DCS3M8XQMPVSA6SZY)
-
Tea kettles are often copper on the bottom. That's the most useful metal for this problem.
-
I use the same tin that I make fuel tanks from. It cuts and bends easily. You can stick it on with clear silicone and it will stay put a very long time. Should you find another way to trim or twist any warp out, you can peal the tab off and remove the silicone. I have also used clear plastic canopy material which mostly hides the tab. For that you need a heat gun to form a bend in the material. I usually then drill a few small holes in the part that glues down so that the silicone can get a grip on the plastic ( poly carbonate I think ). Sig sells it in .030 and .040. I like the .040 better to mold canopies so thats what I have on hand to make tabs.
Dave
-
Quickly!!!! Run down to the local grocery store and peruse the selection of nut and snacks that come in the round cans that have a large, pull off top that is made from aluminum. Try not to pull it back too hard so you don't curl it too much. That is enough malleable metal for several tabs. I used to work in a printing plant and the printing plates from large presses is about .010" to .012" thick and a fairly hard aluminum, but is still able to bend quite well. It makes great tabs. You want to be able to bend it, but also have it stay where you put it. My next choice would be for the copper sheet that was mentioned. K&S has copper sheet in there basic material rack I do believe. It will bend easy, and if the airplane lives long enough, copper hardens with age as it oxidizes and will hold the adjustment. As an alternative, once you figure out how much you need to bend it to make your adjustment, you can make a solid balsa wedge of the appropriate size and angle and glue it in place on the trailing edge and then finish like the rest of the wing.
Type at you later,
Dan McEntee
-
I've used the aluminum roof flashing. Mine was .012 thick and came in a roll. It is pretty much dead soft aluminum of minimal alloy/strength, so it bends easily and will stay there. It doesn't have the annoying memory causing it to curl back to the shape of the extrusion from whence it came (soda can), and it more rigid. (Yes, I've used soda cans....)
And, since you will likely have some left over even after making multiple oversize trim tabs and reflashing your roof, you can make aluminum wing skins for your next speed ship. It's all good....
McDivot
-
I use a piece of TE stock turned around backwards stuck on with double sided sticky tape.
Works great and you can't see it. Plus, it's fully adjustable just by cutting it down in length or width.
Good luck, Jerry
-
I use a piece of TE stock turned around backwards stuck on with double sided sticky tape.
Works great and you can't see it. Plus, it's fully adjustable just by cutting it down in length or width.
Good luck, Jerry
What Jerry said. Once adjusted paint to match.
-
Naah! Don't listen to these guys John!
Here's what you need. Cheap at Home Depot. Just get out the hack-saw!
One more thing: make sure you only put it on the outboard wing!
-
I avoid trim tabs if possible. If a plane flies with one wing high or low, the structure is warped. Instead of trying to compensate, I get rid of the warp. This sometimes takes several tries over a steaming kettle, but when finished, I don't have two opposing forces trying to fight each other.
-
Another source is the little mint tins like Altoids.
-
Naah! Don't listen to these guys John!
Here's what you need. Cheap at Home Depot. Just get out the hack-saw!
One more thing: make sure you only put it on the outboard wing!
No one likes a smart alec (wonder how alec got involved), ain't happening!
-
Naah! Don't listen to these guys John!
Here's what you need. Cheap at Home Depot. Just get out the hack-saw!
One more thing: make sure you only put it on the outboard wing!
Yeah, come on Scott! Those are reserved for only the warpiest of wing warps...
-
if you're gentle, beer cans work pretty good...
-
I avoid trim tabs if possible. If a plane flies with one wing high or low, the structure is warped. Instead of trying to compensate, I get rid of the warp. This sometimes takes several tries over a steaming kettle, but when finished, I don't have two opposing forces trying to fight each other.
Indeed. Folks assume that lift vs. angle of attack is linear, but if the wing is warped, the airplane will roll differently for different loop sizes and directions. A tab can balance it for one flight condition, but it will be out of whack elsewhere.
-
Indeed. Folks assume that lift vs. angle of attack is linear, but if the wing is warped, the airplane will roll differently for different loop sizes and directions. A tab can balance it for one flight condition, but it will be out of whack elsewhere.
Not if he uses my suggestion.... ;D
Guys, we need to encourage John on this, otherwise he'll go back to flying the Randy-plane!
-
I agree with Howard, after all, it makes sense. I could have cut the wing open and gone that way to remove the warp, but I am tired of working on it, it is a real nice plane, and a REAL nice kit (RSM Blue Max) so I put a metal tab on it, that seemed to help. At my age (71), I can be classified as a Sport Flier! I'm a Sport! I saw a sheet metal tab on Ted Fancher's "Trivial Pursuit" back in 2006, if it's good enough for Ted, it's good enough for me! Besides, my Randyplane is really looking beat up! Too many hard landings, upright and inverted! mw~
-
if it's good enough for Ted, it's good enough for me!
That's actually a pretty good motto if you're a stunt builder/flier!
Of course, I saw Bob Hunt's shop last year and some of the stuff he is building. After that my motto has been: "if it's good enough for Bob, it's way more than better enough for me!"
-
Indeed. Folks assume that lift vs. angle of attack is linear, but if the wing is warped, the airplane will roll differently for different loop sizes and directions. A tab can balance it for one flight condition, but it will be out of whack elsewhere.
Yeah, we all know that it is better to remove the warp. But some are better at seeing things than others. If you are at the flying field, it's kind of handy to be able to add a tab to help diagnose a trim problem, and a piece aluminum and some box tape can go a long way to help identify the problem. And sometimes the problem can't be easily fixed.
Type at you later,
Dan McEntee
-
I have several planes that have wing warps impossible to steam, bend , threaten or beat out and fly like 3 legged dogs without trim tabs where needed. I have messed about with solid balsa wedges, bent tin, foam etc. Best of all, use the bionic eye measuring trick and cut one from clear stiff plastic. Bend and mount with double sided tape. Adjustable by rebending or some scissor surgery, and look great coz you don't notice them. Remember, even the Concorde had trim tabs!
-
If you MUST add a trip tab, I prefer something that will not bend once is set correctly for obvious reasons. I use PTEG clear plastic which will not take a permanent set at room temp. I bend at home with a heat gun. It is very rigid and won’t move after it sets.
I adjust for flight trim by cutting the tab to the correct length. The Tab can then be held on with RTV, double sided tape or carpet tape.