What's on your workbench? - Page 3

Mars Flyer · Nov 28, 2005, 10:57 PM

Here are the bones for my Gym Swallow v-tail project. I next have to cut the stab in half and set the 110 degree vee. Then I'll cut the "elevator" portion and trim so I can get both up without bumping together. Next will be the arrow shaft fuse and its pylons and servo mounts. Slow but sure progress...

I'm also trying to hack the snap connections off an 8 cell battery box so I can put some decent batteries in the Optic 6. WARNING to Optic 6 users: even if this works I understand from the Hitec forum that the battery use counter only goes to 199 minutes and then rolls over to 0. Not a major deal but another minor aggravation. I'd be happy to get enough battery capacity to encounter that problem. 80-90 minutes the absolute best I can get on the stock NiCd pack.

Rob

ghee-grose · Nov 28, 2005, 11:12 PM

Rob, I used a dremel tool and ground the posts down on mine. Then I soldered the leads to it. It's a booger to get it plugged in with that big pack though.

Mars Flyer · Nov 28, 2005, 11:20 PM

Gary,

You are way ahead of me. I was just reaching for my Dremel to get the small contact down. The other was easy to remove. Maybe the end result will be worth the trouble. I couldn't find a pack with wires on the internet.

Rob

Moonbeam Six · Nov 28, 2005, 11:33 PM

Jon,

I've been spending a considerable amount of time lately on the RC Groups "DiddleBugs Scale Style" thread. It is easy to get bitten by the Diddle bug. Go to http://www.rcgroups.com/forums/showt...&page=44&pp=15 and check out the ingenuity of those guys. My post with pictures of my Mini Diddle MAX is on page 44. Find the Diddle Champ on page 29 along with .pdf plans. But don't overlook page one so you can see how all this got started. A bit of a warning may be in order. Once you start reading this thread, it is hard to stop.

Frank

nuevo · Nov 28, 2005, 11:35 PM

I guess it's too late, but Radio shack sells connectors like these. I have extras, if you want any.

nuevo · Nov 28, 2005, 11:36 PM

Frank,

Thanks for the details and the link. I'll be reading. Beautiful Mini Diddle MAX. Wow!

Jon

ghee-grose · Nov 28, 2005, 11:37 PM

Beware Rob! When the friction warms things up, the plastic starts to melt. Make sure you position them right, before the plastic sets.

dee-grose · Nov 28, 2005, 11:39 PM

Rob, I'm no aeronautical engineer, but I do remember reading something about v-tails in a magazine a while back. There is some complicated ratio to getting the right tail surface area from just two surfaces as opposed to three. It looks like your new stab is just a copy of the original horizontal stab that you plan to cut in half. It might be too small. Granted on little bitty models like this, it probably doesn't make much of a difference...just thought I'd put the bug in your ear.

afterthought: (rusty gears turning a little more) I think it had something to do with "projections" of the conventional tail surfaces to make the new v-tail surfaces. OK, I'll quit before I hurt myself.

dee-grose · Nov 28, 2005, 11:42 PM

Jon, I think the issue is that there isn't room for such a connector on the end of the little battery holder. I haven't tried it, but I think that is what Gary said.

Mars Flyer · Nov 28, 2005, 11:50 PM

Andy,

The v-tail is not an exact copy. I scaled it up so the total surface area is the same as the stock tail feathers - about a factor of 1.3 scale factor. I'm sure there is a fancy equation somewhere but I think this will be pretty close. The Swallow is extremely stable and seems pretty forgiving. Frank and I have fiddled the wing design pretty significantly and they still fly.

The proof is in the flyin'. We'll see how she does.

Rob

Mars Flyer · Nov 28, 2005, 11:52 PM

Quote:

Originally Posted by dee-grose

Jon, I think the issue is that there isn't room for such a connector on the end of the little battery holder. I haven't tried it, but I think that is what Gary said.

Right. The battery compartment is smaller on the Optic. Probably so you'll have to buy the Hitec battery upgrade

The Flash radios take the Radio Shack box perfectly but not the Optic.

nuevo · Nov 28, 2005, 11:57 PM

Thanks for the battery clarification. Sorry about that.

About the v-tail sizing, here's an article my Mark Drela, and aero prof at MIT. The article assumes you have a conventional tail you want to convert to an equivalent v-tail.

Quick V-Tail Sizing

Moonbeam Six · Nov 28, 2005, 11:58 PM

Jon,

Thanks. There are some good build reports, flight reports, and great pictures posted. They are a cheap, simple, relatively quick and easy build. Flight is confined areas is easier with a small plane.

Frank

Mars Flyer · Nov 29, 2005, 09:20 AM

Jon,

Thanks for the link. I guess my instincts were correct since

" A_vtail = A_vertical + A_horizontal "

is exactly what I used. No rocket science in that

I even checked to make sure that the control surface areas added up to the same.

I'll have to check the relative areas of the tail feathers to calculate the angle. I have already glued up the canonical 110 degree angle but it will be interesting to see how close this comes.

" angle = arctan[ sqrt( A_vertical / A_horizontal ) ] "

Thanks again.

Rob

nuevo · Nov 29, 2005, 10:10 AM

Frank,

Can these Diddle planes be landed at places like NG or the tall grass where I've seen you guys fly? Do they require a parking lot to land?

Jon

Nov 28, 2005, 10:57 PM	#31
Mars Flyer Registered User Join Date: Mar 2004 Location: Huntsville, AL Posts: 393	V-tail swallow Here are the bones for my Gym Swallow v-tail project. I next have to cut the stab in half and set the 110 degree vee. Then I'll cut the "elevator" portion and trim so I can get both up without bumping together. Next will be the arrow shaft fuse and its pylons and servo mounts. Slow but sure progress... I'm also trying to hack the snap connections off an 8 cell battery box so I can put some decent batteries in the Optic 6. WARNING to Optic 6 users: even if this works I understand from the Hitec forum that the battery use counter only goes to 199 minutes and then rolls over to 0. Not a major deal but another minor aggravation. I'd be happy to get enough battery capacity to encounter that problem. 80-90 minutes the absolute best I can get on the stock NiCd pack. Rob Attached Thumbnails Gym Swallow with V-tail mod bones. 84.9 KB · Views: 131 Hacked battery box for Optic 6 hop-up. 54.0 KB · Views: 82

Nov 28, 2005, 11:33 PM	#34
Moonbeam Six Slow Is Sweet Join Date: Jun 2005 Location: Athens, Alabama Posts: 614	Jon, I've been spending a considerable amount of time lately on the RC Groups "DiddleBugs Scale Style" thread. It is easy to get bitten by the Diddle bug. Go to http://www.rcgroups.com/forums/showt...&page=44&pp=15 and check out the ingenuity of those guys. My post with pictures of my Mini Diddle MAX is on page 44. Find the Diddle Champ on page 29 along with .pdf plans. But don't overlook page one so you can see how all this got started. A bit of a warning may be in order. Once you start reading this thread, it is hard to stop. Frank Attached Thumbnails My Mini Diddle MAX. 62.9 KB · Views: 88 Maiden Flight 26.5 KB · Views: 86 This is a Diddle Champ made by Madrob (page 29). 49.4 KB · Views: 102

Nov 28, 2005, 11:35 PM	#35
nuevo Registered User Join Date: May 2002 Posts: 2,020	I guess it's too late, but Radio shack sells connectors like these. I have extras, if you want any. Attached Thumbnails 19.8 KB · Views: 75

Nov 28, 2005, 11:39 PM	#38
dee-grose When's the next fly-in? Join Date: Oct 2003 Location: Tanner, Alabama Posts: 3,144	Rob, I'm no aeronautical engineer, but I do remember reading something about v-tails in a magazine a while back. There is some complicated ratio to getting the right tail surface area from just two surfaces as opposed to three. It looks like your new stab is just a copy of the original horizontal stab that you plan to cut in half. It might be too small. Granted on little bitty models like this, it probably doesn't make much of a difference...just thought I'd put the bug in your ear. afterthought: (rusty gears turning a little more) I think it had something to do with "projections" of the conventional tail surfaces to make the new v-tail surfaces. OK, I'll quit before I hurt myself. Last edited by dee-grose; Nov 28, 2005 at 11:41 PM. Reason: added more ramblings

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Nov 28, 2005, 11:12 PM	#32
ghee-grose Honey, I got more planes! Join Date: Jun 2003 Location: Athens, Alabama Posts: 3,926	Rob, I used a dremel tool and ground the posts down on mine. Then I soldered the leads to it. It's a booger to get it plugged in with that big pack though.

Nov 28, 2005, 11:20 PM	#33
Mars Flyer Registered User Join Date: Mar 2004 Location: Huntsville, AL Posts: 393	Gary, You are way ahead of me. I was just reaching for my Dremel to get the small contact down. The other was easy to remove. Maybe the end result will be worth the trouble. I couldn't find a pack with wires on the internet. Rob

Nov 28, 2005, 11:36 PM	#36
nuevo Registered User Join Date: May 2002 Posts: 2,020	Frank, Thanks for the details and the link. I'll be reading. Beautiful Mini Diddle MAX. Wow! Jon

Nov 28, 2005, 11:37 PM	#37
ghee-grose Honey, I got more planes! Join Date: Jun 2003 Location: Athens, Alabama Posts: 3,926	Beware Rob! When the friction warms things up, the plastic starts to melt. Make sure you position them right, before the plastic sets.

Nov 28, 2005, 11:42 PM	#39
dee-grose When's the next fly-in? Join Date: Oct 2003 Location: Tanner, Alabama Posts: 3,144	Jon, I think the issue is that there isn't room for such a connector on the end of the little battery holder. I haven't tried it, but I think that is what Gary said.

Nov 28, 2005, 11:50 PM	#40
Mars Flyer Registered User Join Date: Mar 2004 Location: Huntsville, AL Posts: 393	Andy, The v-tail is not an exact copy. I scaled it up so the total surface area is the same as the stock tail feathers - about a factor of 1.3 scale factor. I'm sure there is a fancy equation somewhere but I think this will be pretty close. The Swallow is extremely stable and seems pretty forgiving. Frank and I have fiddled the wing design pretty significantly and they still fly. The proof is in the flyin'. We'll see how she does. Rob

Nov 28, 2005, 11:57 PM	#42
nuevo Registered User Join Date: May 2002 Posts: 2,020	Thanks for the battery clarification. Sorry about that. About the v-tail sizing, here's an article my Mark Drela, and aero prof at MIT. The article assumes you have a conventional tail you want to convert to an equivalent v-tail. Quick V-Tail Sizing

Nov 28, 2005, 11:58 PM	#43
Moonbeam Six Slow Is Sweet Join Date: Jun 2005 Location: Athens, Alabama Posts: 614	Jon, Thanks. There are some good build reports, flight reports, and great pictures posted. They are a cheap, simple, relatively quick and easy build. Flight is confined areas is easier with a small plane. Frank

Nov 29, 2005, 09:20 AM	#44
Mars Flyer Registered User Join Date: Mar 2004 Location: Huntsville, AL Posts: 393	Jon, Thanks for the link. I guess my instincts were correct since " A_vtail = A_vertical + A_horizontal " is exactly what I used. No rocket science in that I even checked to make sure that the control surface areas added up to the same. I'll have to check the relative areas of the tail feathers to calculate the angle. I have already glued up the canonical 110 degree angle but it will be interesting to see how close this comes. " angle = arctan[ sqrt( A_vertical / A_horizontal ) ] " Thanks again. Rob

Nov 29, 2005, 10:10 AM	#45
nuevo Registered User Join Date: May 2002 Posts: 2,020	Frank, Can these Diddle planes be landed at places like NG or the tall grass where I've seen you guys fly? Do they require a parking lot to land? Jon