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Old Jul 01, 2014, 02:07 AM
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Joined Jun 2014
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Quote:
Originally Posted by Mal Bond View Post
Hi Dimitri,

Thanks for coming here.
This thread is not very active but a few people keep an eye out for new messages and try to help with advice.
Built up DLGs are almost non existent with the advent of more reasonably priced composite gliders. I have given in to a HobyKing Versus and I am glad I did.
They are consistent and very much quicker to build that an old style 1990s constructed model.
The only thing the Manta has is good looks. It will never be a competition model.

You asked about the build weight of the Fuselage and Canopy with boom.
I would recommend that you target 50g as an all up weight without any fittings. At the top end you could try to be below 60g.
As a further guide you should aim at a finished AUW model with RC gear and everything below 280g. Then you stand a chance of worthwhile performance.
If the model comes out over 300g you will be seriously limiting your flat field and light airs flying.

From what you have said you are at least 40g to high at present so you may need to rethink your construction and what materials you are using. Your aim should be strength without weight.

I do hope this information is helpful.

All the best :-)

Mal :-)
Thank you very much for answering me back. Yes I saw the hobbyking's DLG they are really amazing but I'd like to take a try bulding it. I'm not trying to make it as good as competition models. The reason why I asked for the fuselage weight is mainly because I'm worried about the wing strenght. I already built it but as I'm not very confident with the costruction with D-box and ribs I used the foam core plus balsa cover technique with a full lentgh spar.

Also maybe I said I little wrong. What I intended to ask was th RTF weight of the fusolage with all servos receiver battery and stuff. My empty fusolage weight about 60 grams, with the eletronics is 100 grams but very noseheavy, to have the CG in the right place I had to put 20 grams in the nose.
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Old Jul 01, 2014, 10:06 AM
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United Kingdom, Sidcup
Joined Jun 2012
331 Posts
Manta Weights.

Quote:
Originally Posted by Dimitri89 View Post
Thank you very much for answering me back. Yes I saw the hobbyking's DLG they are really amazing but I'd like to take a try bulding it. I'm not trying to make it as good as competition models. The reason why I asked for the fuselage weight is mainly because I'm worried about the wing strenght. I already built it but as I'm not very confident with the costruction with D-box and ribs I used the foam core plus balsa cover technique with a full lentgh spar.

Also maybe I said I little wrong. What I intended to ask was th RTF weight of the fusolage with all servos receiver battery and stuff. My empty fusolage weight about 60 grams, with the eletronics is 100 grams but very noseheavy, to have the CG in the right place I had to put 20 grams in the nose.
Hi Dimitri,

I think you mean that your Manta is tail heavy when you have to add 20g to the nose to get the CG somewhere near the flying trim. Most DLGs need some nose weight.

One good thing is that you don't seem to be heading to a massive AUW overweight situation.

An advantage of keeping the weight down is that there will be lower stresses on key points like the center section of the wing. It is always a balancing act being strong enough without causing excessive forces in DLGs.

I gave you the naked fuselage and pod assembly target weights. And a target AUW for the flying model. They will be a good guide.

If you use the thread search tool in here you can search all references to "Weight". You can then see all the history of people building and weights they got.

To my recollection the weak point has been the pod/boom joint. So that is a key place.

I know you don't want a competition model but you may want good flat field and light thermal performance. That is what DLG is all about.

Keeping the AUW to 300g will give you a rewarding result. Of course if you are sloping the Manta the AUW will need to be higher and you won't care too much as it will be a light wind slope sorer.

I do hope my feedback is useful even though I have not given detailed breakdowns of weights. You will find those in the thread search.

All the best :-)

Mal :-)
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Old Jul 02, 2014, 02:09 AM
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Joined Jun 2014
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Quote:
Originally Posted by Mal Bond View Post
Hi Dimitri,

I think you mean that your Manta is tail heavy when you have to add 20g to the nose to get the CG somewhere near the flying trim. Most DLGs need some nose weight.

One good thing is that you don't seem to be heading to a massive AUW overweight situation.

An advantage of keeping the weight down is that there will be lower stresses on key points like the center section of the wing. It is always a balancing act being strong enough without causing excessive forces in DLGs.

I gave you the naked fuselage and pod assembly target weights. And a target AUW for the flying model. They will be a good guide.

If you use the thread search tool in here you can search all references to "Weight". You can then see all the history of people building and weights they got.

To my recollection the weak point has been the pod/boom joint. So that is a key place.

I know you don't want a competition model but you may want good flat field and light thermal performance. That is what DLG is all about.

Keeping the AUW to 300g will give you a rewarding result. Of course if you are sloping the Manta the AUW will need to be higher and you won't care too much as it will be a light wind slope sorer.

I do hope my feedback is useful even though I have not given detailed breakdowns of weights. You will find those in the thread search.

All the best :-)

Mal :-)
Thank you again Mal. You've been very helpful, and yes I meant tailheavy. Now I'm in this situation: wing weights 165 grams and fusolage 120 grams so the RTF wheigt is 285. It's not that bad, but I'm thinking about rebuilding the fusolage. Probably I lighter tail boom (actually it weights 32 grams) will save weight, and also will make the plane no more tailheavy.
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Old Jul 02, 2014, 05:12 AM
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United Kingdom, Sidcup
Joined Jun 2012
331 Posts
Some details from a middle of the road DLG

Quote:
Originally Posted by Dimitri89 View Post
Thank you again Mal. You've been very helpful, and yes I meant tailheavy. Now I'm in this situation: wing weights 165 grams and fusolage 120 grams so the RTF wheigt is 285. It's not that bad, but I'm thinking about rebuilding the fusolage. Probably I lighter tail boom (actually it weights 32 grams) will save weight, and also will make the plane no more tailheavy.
Hi Dimitri :-)

I am going to repeat the stats of my Versus so you can see some good targets for every aspect of a middle of the road DLG.

THIS IS NOT THE STATS FOR A MANTA !!!!!

http://www.rcgroups.com/forums/showt...us+dlg&page=23
Post #332 :-

Welcome to the build of the Versus :-)
There is loads of research in this Versus thread to help. This is a summary of the Versus stats :-)

The Out of The Box (OOTB) Details.

Fin/Rudder 6.7g
Tailplane/Elevator 10.6g
Boom 15.6g
Carbon and Glass Cloth 3.8g
Accessories 23.4g
Fus w/canopy 39.9g
Right Wing 68.9g
Left Wing 67.5g
Total Dry Weight 236.4g

236.4g = 8.34 oz

list of expectations:-

Wings 136.4g (OOTB out of the box)
Fuse 39.9g (OOTB)
Boom 15.6g (OOTB)
Tail 17.3g (OOTB)
Control linkage 2.0g Pull Spring
Accs 21.0g (pull spring setup)
Glue 10.0g (glue and glassing)

Servos 25.0g (4 x 6g)
Rx 4.0g (AR6100)
Cables 8.0g
Lipo 10.0g (350mah 1S round lipo)
BEC 2.9g (Voltage Booster to 5v)

TOTAL 292.1g (no lead planned)

Expected weight savings at Tail end -10g, ballast -15 to 20g = -25g

Out of the box length 1185mm (should be 1135mm)

Proposed wing TE to LE of tailplane 500mm.

Please note that I shortened the OOTB boom by 50mm so the overall length was 1135mm, to reduce weight both ends.
HobbyKing confirmed that 1135mm is the correct overall length.
I also had the option to make lightening holes in the tail parts and taper the Elevator and rudder to knife edge for more overall weight reduction.

The AUW ended up at 300g and it flies very well.

I do hope these Versus stats are helpful as a guide.

All the best.

Mal :-)
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Old Jul 02, 2014, 08:44 AM
Registered User
Joined Jun 2014
4 Posts
Quote:
Originally Posted by Mal Bond View Post
Hi Dimitri :-)

I am going to repeat the stats of my Versus so you can see some good targets for every aspect of a middle of the road DLG.

THIS IS NOT THE STATS FOR A MANTA !!!!!

http://www.rcgroups.com/forums/showt...us+dlg&page=23
Post #332 :-

Welcome to the build of the Versus :-)
There is loads of research in this Versus thread to help. This is a summary of the Versus stats :-)

The Out of The Box (OOTB) Details.

Fin/Rudder 6.7g
Tailplane/Elevator 10.6g
Boom 15.6g
Carbon and Glass Cloth 3.8g
Accessories 23.4g
Fus w/canopy 39.9g
Right Wing 68.9g
Left Wing 67.5g
Total Dry Weight 236.4g

236.4g = 8.34 oz

list of expectations:-

Wings 136.4g (OOTB out of the box)
Fuse 39.9g (OOTB)
Boom 15.6g (OOTB)
Tail 17.3g (OOTB)
Control linkage 2.0g Pull Spring
Accs 21.0g (pull spring setup)
Glue 10.0g (glue and glassing)

Servos 25.0g (4 x 6g)
Rx 4.0g (AR6100)
Cables 8.0g
Lipo 10.0g (350mah 1S round lipo)
BEC 2.9g (Voltage Booster to 5v)

TOTAL 292.1g (no lead planned)

Expected weight savings at Tail end -10g, ballast -15 to 20g = -25g

Out of the box length 1185mm (should be 1135mm)

Proposed wing TE to LE of tailplane 500mm.

Please note that I shortened the OOTB boom by 50mm so the overall length was 1135mm, to reduce weight both ends.
HobbyKing confirmed that 1135mm is the correct overall length.
I also had the option to make lightening holes in the tail parts and taper the Elevator and rudder to knife edge for more overall weight reduction.

The AUW ended up at 300g and it flies very well.

I do hope these Versus stats are helpful as a guide.

All the best.

Mal :-)
Yes it's very usefull. I'll take some inspiration while bulding a new fuselage. I'll let you know how it will be at the end thank you again, I hope to post some good new in the near future
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Old Oct 26, 2014, 04:09 AM
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Joined Jul 2004
26 Posts
Hi All,

Does anyone know a supplier of CF tailbooms in Australia?

BR

Timbo
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