Lighter wing loading???
10-05-2009 | 01:41 PM
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From: Nutley,
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Lighter wing loading???
I have been looking to buy a new plane, however I have no idea what I want. Cant do 50cc right now as I cant transport...and the current 1.20 size planes dont really speak to me. For now I think I might decide to strip my showtime and recover and lighten. After a very rough calculation my wing loading is about 22 oz/sq in. If I was able to bring it down to say about 19 oz/sq in....would this make a big difference in performance? Looks like I might be able to save 5 oz by swapping components(below). Again rough calc, would need to save 8 oz to hit the 19 oz/ sq in. mark. I might be off.
Anyway I am currently using:
Dubro HD control horns all around - these are all metal so im sure I could save an ounce by switching all to something lighter
Landing gear - could prob save 1 - 2 ounces by going CF
Throttle servo - switching to an HS-82 would save one ounce
APC prop - going to wood would save one ounce
Possibly i could find lighter wheels - dont know if the difference will be that much
Axles - currently using 5/32( i think) dubro. Probably bigger than I need. Dont know if its worth the hassle of going down a size.
What do you guys think? Wondering if the 3 oz/sq in wing load difference would make a noticeable difference in flight.
Any input would be great.
Anyway I am currently using:
Dubro HD control horns all around - these are all metal so im sure I could save an ounce by switching all to something lighter
Landing gear - could prob save 1 - 2 ounces by going CF
Throttle servo - switching to an HS-82 would save one ounce
APC prop - going to wood would save one ounce
Possibly i could find lighter wheels - dont know if the difference will be that much
Axles - currently using 5/32( i think) dubro. Probably bigger than I need. Dont know if its worth the hassle of going down a size.
What do you guys think? Wondering if the 3 oz/sq in wing load difference would make a noticeable difference in flight.
Any input would be great.
10-05-2009 | 02:06 PM
#2
RE: Lighter wing loading???
Lighter is always better but I dont think it will change the plane up that much. Sounds like you are looking for some more power. What engine are you running?
10-05-2009 | 03:16 PM
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From: Nutley,
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RE: Lighter wing loading???
Ive got enough power. Using a Saito 91 with a 14x7 apc. Figure if I can make changes...just to keep it interesting and see if I can get improved performance.
10-05-2009 | 04:21 PM
#4
RE: Lighter wing loading???
A reduction in 3 oz per sq.ft. would require a total weight reduction of 15 ounces wich is substantial. I don;'t think the changes you listed will be enough to get you the 15 oz reduction you would need.
Convert sq in. to sq ft:
From the web, The plane has sq ft of wing at 716 sq in. / 144 sq inches 4.97 sg ft. of wing
Convert weight to ounces:
The web has the planes weight listed at 7.2 lbs x 16 oz = 115.2 ounces.
Divide total ounces (less fuel) by sg. ft. of wing to calculate wing loading per sq ft.
Weight of plane: 115.2 ounces ................. 112..............105 oz........... 100 oz
Wing loading: 23.17 oz/sq ft.....................22.53............21.12..... ........20.12
You can perform the above in one step (weight in lbs x 2304 (fixed constant) \ Wing Area in sq inches.
So (7.2lbs x 2304) / 716 = 23.16 oz the beginning number.
I got this info from the airfield models site... fantastic reference material convering many areas http://www.airfieldmodels.com/inform...urce/index.htm
Convert sq in. to sq ft:
From the web, The plane has sq ft of wing at 716 sq in. / 144 sq inches 4.97 sg ft. of wing
Convert weight to ounces:
The web has the planes weight listed at 7.2 lbs x 16 oz = 115.2 ounces.
Divide total ounces (less fuel) by sg. ft. of wing to calculate wing loading per sq ft.
Weight of plane: 115.2 ounces ................. 112..............105 oz........... 100 oz
Wing loading: 23.17 oz/sq ft.....................22.53............21.12..... ........20.12
You can perform the above in one step (weight in lbs x 2304 (fixed constant) \ Wing Area in sq inches.
So (7.2lbs x 2304) / 716 = 23.16 oz the beginning number.
I got this info from the airfield models site... fantastic reference material convering many areas http://www.airfieldmodels.com/inform...urce/index.htm
10-05-2009 | 04:34 PM
#5
Senior Member
RE: Lighter wing loading???
Heck, try all the changes and find out. That's the beauty of our hobby.
Now, about some of your expectations.
Weigh your gear before you swap in the CF. I've yet to find 40 size CF that's lighter than the usual aluminum nor 60-90 size either. It's not a given that CF is lighter than what's found on lots of ARFs.
There really are savings to be found in wheels, but only if the OEMs are heavy. Want to save weight in the gear? Get rid of the axles, weigh your wheels and see if they can be swapped out for lighter and THEN..........
Then swap out those axles with CF tubes in aluminum tubing. Epoxy the CF into the tubing and the tubing into the holes in the struts. Takes time? A bit. But you'll get an honest weight savings. I've got a number of old (built 5 years ago) ARFs that came with HUGE iron (ok, metal) axles that got the custom made axles. They do take plywood plates sandwiched against the strut to fully support the composite (REALLY composite : aluminum+CF) axle. The struts aren't thick enough without additional thickness and that small amount of ply is perfect.
And then...........
and then.............
Go fly the sucker and report back. Good chance you'll think it's awesome.... first couple of times you take 'er out........ and then............ you'll notice that getting a good needle setting instead of a bad one makes more difference. But that's not a given.
Everything is worth trying.
I'd bet that swapping the prop might do as much. And double the bet if you took 4 or 5 props out and tested to find the best.
It does sound like you're got something worth trying. Let us know how it works out.
Now, about some of your expectations.
Weigh your gear before you swap in the CF. I've yet to find 40 size CF that's lighter than the usual aluminum nor 60-90 size either. It's not a given that CF is lighter than what's found on lots of ARFs.
There really are savings to be found in wheels, but only if the OEMs are heavy. Want to save weight in the gear? Get rid of the axles, weigh your wheels and see if they can be swapped out for lighter and THEN..........
Then swap out those axles with CF tubes in aluminum tubing. Epoxy the CF into the tubing and the tubing into the holes in the struts. Takes time? A bit. But you'll get an honest weight savings. I've got a number of old (built 5 years ago) ARFs that came with HUGE iron (ok, metal) axles that got the custom made axles. They do take plywood plates sandwiched against the strut to fully support the composite (REALLY composite : aluminum+CF) axle. The struts aren't thick enough without additional thickness and that small amount of ply is perfect. And then...........
and then.............
Go fly the sucker and report back. Good chance you'll think it's awesome.... first couple of times you take 'er out........ and then............ you'll notice that getting a good needle setting instead of a bad one makes more difference. But that's not a given.
Everything is worth trying.
I'd bet that swapping the prop might do as much. And double the bet if you took 4 or 5 props out and tested to find the best.
It does sound like you're got something worth trying. Let us know how it works out.
10-05-2009 | 06:05 PM
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From: Nutley,
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RE: Lighter wing loading???
ORIGINAL: KitBuilder
A reduction in 3 oz per sq.ft. would require a total weight reduction of 15 ounces wich is substantial. I don;'t think the changes you listed will be enough to get you the 15 oz reduction you would need.
Convert sq in. to sq ft:
From the web, The plane has sq ft of wing at 716 sq in. / 144 sq inches 4.97 sg ft. of wing
Convert weight to ounces:
The web has the planes weight listed at 7.2 lbs x 16 oz = 115.2 ounces.
Divide total ounces (less fuel) by sg. ft. of wing to calculate wing loading per sq ft.
Weight of plane: 115.2 ounces ................. 112..............105 oz........... 100 oz
Wing loading: 23.17 oz/sq ft.....................22.53............21.12..... ........20.12
You can perform the above in one step (weight in lbs x 2304 (fixed constant) \ Wing Area in sq inches.
So (7.2lbs x 2304) / 716 = 23.16 oz the beginning number.
I got this info from the airfield models site... fantastic reference material convering many areas http://www.airfieldmodels.com/inform...urce/index.htm
A reduction in 3 oz per sq.ft. would require a total weight reduction of 15 ounces wich is substantial. I don;'t think the changes you listed will be enough to get you the 15 oz reduction you would need.
Convert sq in. to sq ft:
From the web, The plane has sq ft of wing at 716 sq in. / 144 sq inches 4.97 sg ft. of wing
Convert weight to ounces:
The web has the planes weight listed at 7.2 lbs x 16 oz = 115.2 ounces.
Divide total ounces (less fuel) by sg. ft. of wing to calculate wing loading per sq ft.
Weight of plane: 115.2 ounces ................. 112..............105 oz........... 100 oz
Wing loading: 23.17 oz/sq ft.....................22.53............21.12..... ........20.12
You can perform the above in one step (weight in lbs x 2304 (fixed constant) \ Wing Area in sq inches.
So (7.2lbs x 2304) / 716 = 23.16 oz the beginning number.
I got this info from the airfield models site... fantastic reference material convering many areas http://www.airfieldmodels.com/inform...urce/index.htm
thank you for the site!!
10-05-2009 | 06:12 PM
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From: Nutley,
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RE: Lighter wing loading???
ORIGINAL: da Rock
Heck, try all the changes and find out. That's the beauty of our hobby.
Now, about some of your expectations.
Weigh your gear before you swap in the CF. I've yet to find 40 size CF that's lighter than the usual aluminum nor 60-90 size either. It's not a given that CF is lighter than what's found on lots of ARFs.
There really are savings to be found in wheels, but only if the OEMs are heavy. Want to save weight in the gear? Get rid of the axles, weigh your wheels and see if they can be swapped out for lighter and THEN.......... Then swap out those axles with CF tubes in aluminum tubing. Epoxy the CF into the tubing and the tubing into the holes in the struts. Takes time? A bit. But you'll get an honest weight savings. I've got a number of old (built 5 years ago) ARFs that came with HUGE iron (ok, metal) axles that got the custom made axles. They do take plywood plates sandwiched against the strut to fully support the composite (REALLY composite : aluminum+CF) axle. The struts aren't thick enough without additional thickness and that small amount of ply is perfect.
And then...........
and then.............
Go fly the sucker and report back. Good chance you'll think it's awesome.... first couple of times you take 'er out........ and then............ you'll notice that getting a good needle setting instead of a bad one makes more difference. But that's not a given.
Everything is worth trying.
I'd bet that swapping the prop might do as much. And double the bet if you took 4 or 5 props out and tested to find the best.
It does sound like you're got something worth trying. Let us know how it works out.
Heck, try all the changes and find out. That's the beauty of our hobby.
Now, about some of your expectations.
Weigh your gear before you swap in the CF. I've yet to find 40 size CF that's lighter than the usual aluminum nor 60-90 size either. It's not a given that CF is lighter than what's found on lots of ARFs.
There really are savings to be found in wheels, but only if the OEMs are heavy. Want to save weight in the gear? Get rid of the axles, weigh your wheels and see if they can be swapped out for lighter and THEN..........
Then swap out those axles with CF tubes in aluminum tubing. Epoxy the CF into the tubing and the tubing into the holes in the struts. Takes time? A bit. But you'll get an honest weight savings. I've got a number of old (built 5 years ago) ARFs that came with HUGE iron (ok, metal) axles that got the custom made axles. They do take plywood plates sandwiched against the strut to fully support the composite (REALLY composite : aluminum+CF) axle. The struts aren't thick enough without additional thickness and that small amount of ply is perfect. And then...........
and then.............
Go fly the sucker and report back. Good chance you'll think it's awesome.... first couple of times you take 'er out........ and then............ you'll notice that getting a good needle setting instead of a bad one makes more difference. But that's not a given.
Everything is worth trying.
I'd bet that swapping the prop might do as much. And double the bet if you took 4 or 5 props out and tested to find the best.
It does sound like you're got something worth trying. Let us know how it works out.
Your axle mod sounds interesting! Got a picture? Want to get a clearer vision of how the axle/ply meet the gear.
Im gonna move to the 14x7 Xaor anyway...so the reduction is nice...small but nice. I had one and broke it before even being able to take off
grrrrrr!I was just looking for something fun to do and make it more my own....and maybe get a little better performance out of it. If flies fine as it is....but could always try and make it better.
Thanks guys.
10-05-2009 | 08:12 PM
#8
Senior Member
RE: Lighter wing loading???
I've only bought 3 CF gear that I can remember. Every one was ounces heavier than the aluminum they were to replace. They've all been much stiffer, so stiff in fact, that I've pulled them from two planes. Sold the other.
I'll take a picture next time I've got one of the CF axled planes down from their racks. I don't fly them much anymore.
The pads really only sandwich the end of the gear leg. They're to add width to support the axle where it goes through the leg. No special shape or anything, they're just the bread in a gear leg sandwich. If just the axle was sticking through that rather thin aluminum gear leg, there wouldn't be enough surface area holding the axle at a right angle to the leg to take the forces transmitted through the wheel up the leg. With the pads, the forces are carried by the ply and the leg, not just the leg.
Try to imagine a thick plywood washer. The axle is a tight fit through that washer. The axle sticks through the leg with a washer one each side of the leg. All that is epoxied solid. The epoxy bonds the washers and axle to the leg and basically turns all that into one solid composite.
BTW, the wheel is held on the axle with a small washer that's epoxied on. Another simple and lightweight detail. It's also more streamlined. The washer is against the wheel of course with about 1/32" of the axel sticking out. The epoxy is a fillet around the washer. I figure the streamlining alone gives the airplane maybe 15-20mph greater top speed..............
on each side...........
I'll take a picture next time I've got one of the CF axled planes down from their racks. I don't fly them much anymore.
The pads really only sandwich the end of the gear leg. They're to add width to support the axle where it goes through the leg. No special shape or anything, they're just the bread in a gear leg sandwich. If just the axle was sticking through that rather thin aluminum gear leg, there wouldn't be enough surface area holding the axle at a right angle to the leg to take the forces transmitted through the wheel up the leg. With the pads, the forces are carried by the ply and the leg, not just the leg.
Try to imagine a thick plywood washer. The axle is a tight fit through that washer. The axle sticks through the leg with a washer one each side of the leg. All that is epoxied solid. The epoxy bonds the washers and axle to the leg and basically turns all that into one solid composite.
BTW, the wheel is held on the axle with a small washer that's epoxied on. Another simple and lightweight detail. It's also more streamlined. The washer is against the wheel of course with about 1/32" of the axel sticking out. The epoxy is a fillet around the washer. I figure the streamlining alone gives the airplane maybe 15-20mph greater top speed..............
on each side...........
10-05-2009 | 08:36 PM
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From: Nutley,
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RE: Lighter wing loading???
ORIGINAL: da Rock
I've only bought 3 CF gear that I can remember. Every one was ounces heavier than the aluminum they were to replace. They've all been much stiffer, so stiff in fact, that I've pulled them from two planes. Sold the other.
I'll take a picture next time I've got one of the CF axled planes down from their racks. I don't fly them much anymore.
The pads really only sandwich the end of the gear leg. They're to add width to support the axle where it goes through the leg. No special shape or anything, they're just the bread in a gear leg sandwich. If just the axle was sticking through that rather thin aluminum gear leg, there wouldn't be enough surface area holding the axle at a right angle to the leg to take the forces transmitted through the wheel up the leg. With the pads, the forces are carried by the ply and the leg, not just the leg.
Try to imagine a thick plywood washer. The axle is a tight fit through that washer. The axle sticks through the leg with a washer one each side of the leg. All that is epoxied solid. The epoxy bonds the washers and axle to the leg and basically turns all that into one solid composite.
BTW, the wheel is held on the axle with a small washer that's epoxied on. Another simple and lightweight detail. It's also more streamlined. The washer is against the wheel of course with about 1/32'' of the axel sticking out. The epoxy is a fillet around the washer. I figure the streamlining alone gives the airplane maybe 15-20mph greater top speed.............. on each side...........
I've only bought 3 CF gear that I can remember. Every one was ounces heavier than the aluminum they were to replace. They've all been much stiffer, so stiff in fact, that I've pulled them from two planes. Sold the other.
I'll take a picture next time I've got one of the CF axled planes down from their racks. I don't fly them much anymore.
The pads really only sandwich the end of the gear leg. They're to add width to support the axle where it goes through the leg. No special shape or anything, they're just the bread in a gear leg sandwich. If just the axle was sticking through that rather thin aluminum gear leg, there wouldn't be enough surface area holding the axle at a right angle to the leg to take the forces transmitted through the wheel up the leg. With the pads, the forces are carried by the ply and the leg, not just the leg.
Try to imagine a thick plywood washer. The axle is a tight fit through that washer. The axle sticks through the leg with a washer one each side of the leg. All that is epoxied solid. The epoxy bonds the washers and axle to the leg and basically turns all that into one solid composite.
BTW, the wheel is held on the axle with a small washer that's epoxied on. Another simple and lightweight detail. It's also more streamlined. The washer is against the wheel of course with about 1/32'' of the axel sticking out. The epoxy is a fillet around the washer. I figure the streamlining alone gives the airplane maybe 15-20mph greater top speed..............
on each side...........
10-05-2009 | 09:43 PM
#11
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RE: Lighter wing loading???
ORIGINAL: AirWizard
If you want to make a real difference get a YS 110
If you want to make a real difference get a YS 110
I too have found CF gears to weigh more then aluminmum gear and my old drill will put holes in things besides balsa wood, makes very light aluminum gears. Ever think about bending your own LG from piano wire?? Very light and strong. Sometimes it can get ugly but I have also made up some very nice looking LG.
10-08-2009 | 06:56 AM
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From: Humble, TX
RE: Lighter wing loading???
You can always change out your pushrods with CF tube and light 1/8 inch pushrod ends. Extremly strong and very light.
They can be found [link=http://www.connectorsrc.com]HERE[/link]
They can be found [link=http://www.connectorsrc.com]HERE[/link]
10-08-2009 | 07:51 AM
#14
RE: Lighter wing loading???
I think the 15x4 like prop is the best idea. You have a lot of pitch for a 3D plane with the 14X7. The biggest problem with reduceing weight is cost. CF gear, pushrods, new servo, hardware will put you at $150 in no time; Your halfway there to aYS 110 or a new plane.
10-08-2009 | 12:22 PM
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RE: Lighter wing loading???
Thanks guys. I am using carbon rods already. Ive been thinking about the prop and think it certianly is too fast for 3d. Flies great pattern though. Will try 14x6, 15x6 and 15x4 at some point.
Thinking faster servos would be nice. Currently using Hitec hs 5475 on elev and ailerons at .18 sec w/ 6 volt. Wondering if faster would be better. Would Hitec hs 625mg at .13 sec w/ 6 volt be a worth while improvement even though they are not digital????
Plane calls for standard servos...would mini hitec MGs work? Hitec 225mg - 67 oz - .11 sec at 6v???
Thinking faster servos would be nice. Currently using Hitec hs 5475 on elev and ailerons at .18 sec w/ 6 volt. Wondering if faster would be better. Would Hitec hs 625mg at .13 sec w/ 6 volt be a worth while improvement even though they are not digital????
Plane calls for standard servos...would mini hitec MGs work? Hitec 225mg - 67 oz - .11 sec at 6v???
