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Old May 07, 2004, 08:31 PM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
388 Posts
From HLG to DLG...Apogee?

Me and a fellow club member here in PA have interest in building a DLG model. He suggested Apogee becuase of the free plans. I have not thought much about the options but free plans are nice and I know my simulator has the Apogee in it (SSS).

He's interested in having a model that will DLG...I don't mind between DLG or HLG but so I think I'd build my plane for both.

36" Apogee is what he's planning materials for. To make it DLG-ready (Apogee is not intended for DLG by-design) he plans to put a layer of 1/64 ply top and bottom and maybe some fiberglass too.

Can anyone recommend what to do to make an Apogee ready for DLG? Or...can anyone recommend a non-composite and easy to build (balsa) DLG plane? Can be built-up or solid balsa like the Apogee.

My fellow pilot asked me to ask you guys about how a single Lipo cell will do in a HLG/DLG and also about what the favored servos are for small, light, HLG/DLGs.

Thanks much,
John
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Old May 08, 2004, 01:15 AM
AMA 562227
Three-Wire's Avatar
United States, CA, Mojave
Joined Jan 2003
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I don't have one, but I'm sure thinking about getting one as soon as I get paid again...

Gambler+

Gambler+ Build Thread
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Old May 08, 2004, 07:54 AM
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Germantown, Maryland
Joined Apr 2004
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You may find some help with the Apogee and the question of discus launching it in one or both of the following YAHOO groups;

http://groups.yahoo.com/group/SALglider/
http://groups.yahoo.com/group/Allegro-Lite/

I did a quick search of the SALgliders message archives and came up with the following results for "discus apogee";

messages 6338, 3117, 3115, and 1877

There may be others and you should search the files and messages of the Allegro-Lite group also.

For servos I can recomend the following;

http://adesigner.com/hobbies/DEALS.HTM

I have used the HES2003 and HES 490 servos for a 42" span rocket glider which was also discus launchable. The centering of the servos is not the best compared to larger servos but these are very light and thin servos and they are adequate for very small models. I would not recomend these servos for a full size discus launch model except maybe for a four wing servo model where each servo only operates a small flap or aileron rather than a full span flaperon.

Phil
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Old May 08, 2004, 08:24 AM
Registered User
Germantown, Maryland
Joined Apr 2004
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I was just checking out the Polecat Aeroplane Works site and noticed that he also sells the HES 2003 and HES 490 servos. He has a new accessories page which lists some very DLG componenets. You can buy separate tails, fuselages, wings, and even stab mounts. All top quality high performance competition stuff.

Phil
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Old May 08, 2004, 10:05 AM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
388 Posts
Thanks a lot for the info, Phil and 3-Wire.

Is there a rule-of-thumb about vertical stabilizer size for a DLG? Any tips? Does length of boom make a difference?

Also, what are some places to buy tailboom material from? CF tube...
tailboom.com has some larger tailbooms.

Is the Hitec Electron 6 a good rx for small HLGs? I currently have one in my GL...works great...and recently I found a place that sells them for a few bucks less than most places.

Thanks again guys,
John
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Old May 08, 2004, 10:38 AM
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Lindenwold, NJ, USA
Joined Dec 2000
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If you look at the plans site there is a plan for the discus launch version of the Apogee.
If you don't mind waiting for the plans you could build the Bug.
http://groups.yahoo.com/group/BugHLG/

The Gambler+ plans are available although with the price difference between the plans ($16) and the complete kit ($65), it makes sense to go with the kit.

John
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Old May 08, 2004, 12:49 PM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
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Which plans page is this you mention...I don't think the page I'm looking at Apogee plans on has the wood DLG plans. I see DLG plans for the composite version...but not the wood one.
~John
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Old May 08, 2004, 02:17 PM
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Germantown, Maryland
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Quote:
Originally Posted by Seared Ice
Is there a rule-of-thumb about vertical stabilizer size for a DLG? Any tips? Does length of boom make a difference?

Also, what are some places to buy tailboom material from? CF tube...
tailboom.com has some larger tailbooms.
For a DLG model you want a large vertical fin that extends partially below the boom. Just imitate the current contest models such as Taboo or XP3/4. A longer boom with a smaller fin would act the same as a shorter boom with a larger fin.

The Allegro boom that Tailboom.com sells is the best boom for a full size competition DLG model. For smaller models you want an arrow shaft/ kite spar type boom. Here is a link for those;

http://www.aviasport.net/catalog/carbon/index.htm

This should take you to a page of "G-Force tapered Kite Spars". Most kits and plans will specify or use one of these and you will find these sold by many other distributors as well. This is the most direct and least expensive source that I am aware of. This is my source for micro carbon rods also. I have always ordered by phone. The site has a phone number listed, I did not see any prices or any way to order from the site so I guess you need to call to order. The carbon tube kite spars run about $5 each and small 4' micro carbon rods are about $1 each. They will cut micro carbon rods to any length you like and do not apear to have a minimum order.

I used the T-285-32-ULT G-Force ultra light for my 42" span rocket glider/DLG model.

Phil
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Old May 08, 2004, 03:03 PM
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West Boylston, MA
Joined Feb 2003
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Proposed DLG Mods to Wood Apogee

I'm just now planning my wood Apogee DLG building project. I'm not saying I know this will work, but I intend to try the following for DLG reinforcements:

1) I'm going to add carbon spar caps top and bottom to my balsa wings, much like those on the composite molded Apogee. After cutting the outline of the wing and tapering the blank, I hope to sand a shallow groove (Ron Gauthier's idea) at the airfoil high point, laminate a tapered carbon tow ribbon into the groove and fill the groove with lightweight sanding sealer, all before sanding the airfoil using Mark's recommended method from the Apogee site.

2) I plan to put similar carbon tow tape reinforcements on the outside of both sides and bottom of the pod, from nose to boom.

3) Mark said in a post on SALGlider to use the fat end of a Avia Skinny SUL kite boom, which can be had (along with many others) at Goodwinds' (http://www.goodwindskites.com/merch/....wrappedcarbon).

4) Oh yea! And I'm going to use a cruciform tail, sized to match the effective horizontal area of the v-tail, and enlarging the effective vertical area proportionally to increase the C-sub-v to 0.04, like the SuperGee.

Otherwise, it'll be a stock wood Apogee.

One more thing I'm considering: You need ~3/8 thick, 4-4.5 lb. wing stock, but I have only 5 lb., 1/4". I might try tapering two pieces in advance, then hollowing the inside faces somewhat (following the anticipated airfoil contour) before laminating them with model airplane cement (sandable). I'd hope this slightly hollowed wing would compensate for the 5 lb. wood.

(Mark Drela: I'd very much appreciate your comments on the above plan. Thanks.--MT)

Thermals,

Marc
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Old May 08, 2004, 08:03 PM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
388 Posts
Thanks again guys! Rcgroups is great!
So what are the surface areas of the fin/stab you're making, marc? One thing I read was that by thinning the airfoil 10-15% with 5lb wood it makes up for the difference in weight. I see yours will have to be thinner because of how yours is 1/4" thick rather than 3/8" thick.
The guy I'm figuring this out with is finding a place to get 4lb balsa.
Anybody have anything else to add? I've still got some questions unanswered from my first post in this thread...
~John
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Old May 11, 2004, 06:43 AM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
388 Posts
We ordered servos and lipos from Balsa Products (balsapr.com)
He's already got the receivers.
Can anyone else give me input?
Thanks a lot!
~John
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Old May 11, 2004, 07:54 AM
Good thing balsa floats!
Rain City Flyer's Avatar
Seattle
Joined Sep 2001
770 Posts
Ice - There is a listing on the Charles River site for a tip launch rated Apogee. It is however, intended for composite construction rather than balsa. Give it a once over.

You can even scratch build a small SAL plane. Check this out: It's easier to build the wing since it is part solid d-box and part ribs rather than all balsa.

42" span, 4" chord, weighs about 4 ounces, launches to about 80 feet.

Enjoy your scratch building project.

Chris in Seattle
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Old May 11, 2004, 08:16 AM
Gambler-AG DLG Designer
Allan Wright's Avatar
Lee, NH, USA
Joined Jun 2001
5,188 Posts
D-box is very key in gettng a balsa DLG scratch built working. Either solid or hollow will work. I use hollow with CF reinforcement at the spar and a hardwood dowel at the LE. I've used CF tube on my LE but it is heavier than you need and overkill strength wise. The killer on thes wings is tortional stiffness. If your wing isn't stiff tortionally it will flutter on launch and explode. The 2nd thing you need is enough strength at the peg to handle the G-forces of a full DLG throw. Get those two down and get a boom stiff enough and you'll be damn close.

The Avia booms are nice and light, but depending on the size of your plane may be too weak. If you're sticking to Mosquito class they're great. Above that I like the Skyshark series. They're heavier but a LOT stronger. Oh and if you get up to 1.5 meter span go directly to Rick Walba (www.tailboom.com) and get his DLG boom. It's the best.
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Old May 11, 2004, 02:52 PM
The Airplane Gremlin
Seared Ice's Avatar
United States, PA, Pittsburgh
Joined Jun 2003
388 Posts
What qualifies as "Mosquito Class"?

How does a SAL differ from a DL?

So what vertical stabilizer surface area should I be thinking about for a plane with wingspan around 36" and distance from wing TE to vertical stabilizer LE of about 12"?

~John
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Old May 11, 2004, 03:17 PM
Good thing balsa floats!
Rain City Flyer's Avatar
Seattle
Joined Sep 2001
770 Posts
I believe Mosquito limits are .75 meters (29in) for the wingspan. But to be honest, I don't know anyone who holds contests in this class.

There are many posts about tail volume (do a search), but I tend to go for about 10% of main wing area for the horizontal stab (full flying) and close to the same area (but generally less) for the vertical. There are many qualified experts on this topic. Poke through past posts for the gems of knowledge or wing it and see how it works.

With a full flying stab and tape hinges for the elevator, it's simple to make interchangeable parts to test the impact on your airframe. I use 3/32 balsa and waterborne polyurethane to save weight. No covering. A little glass reinforcing at the boom mount and you are good to go. I've never broken a tail yet.

Have fun with your scratch building project.

Chris in Seattle
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