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Old Oct 11, 2010, 11:47 PM
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Cheap thrills with Ramrod

Not absolutely sure this belongs here, but here goes:
I have just maidened what I call my Ramrod 100. It is a scaled down Ramrod 250, with a wingspan of 25 inches and a wing area of 100 sq.in.
I had aimed for a total weight of 2 oz. max, and the final product weighs 53 gram (1.9 oz.).
The model is built mainly from 1/32 balsa, with the exceptions of the wing spars of 1/16, and wing and tailplane trailing edges, which are cut and sanded from 3/32 sheet; the pylon is a piece of 3/32 sheet. Covering is laminating film, of the semi-matt kind.
I reduced the number of ribs of both the wing and tailplane, with a 40 mm spacing.
Power is a GWS LPS B2B 5:1 geared motor which I had laying around and a 5x4.3 GWS prop. Battery is 2xKokam 135 mAh 4 gram Lipo cells of many years' vintage. They still work OK for about 7 minutes of motor run. ESC is one of my own trusty JMP7 and the receiver is an FrSky V8R4 which weighs 2.7 gram when the wrapping is removed.
Ramrod 100 flies on rudder and throttle only. The servo is an even older Wes Technik 2.5 gram type (nowadays, I would use the $4.29 "HobbyKing Ultra Micro Servo 1.7g for 3D Flight".
I had to guess at the rudder size, the resulting control is positive, yet not unduly sensitive. This was a surprise as I remember how critical any change of the rudder tab the 1/2A power models of my youth seemed to be. Also, the 1° wing incidence relative to the tailplane, and the 85% C.o.G. position shown on the Ramrod 250 drawing came out well. A classic case of "straight from the building board". This says much about the excellence of Ron Saint Jean's design, which can be scaled up or down with always good results.
The only thing I would change is the motor gear ratio, down to 4:1, to either give a quicker climb with the same prop, or the same climb with a smaller prop. With a smaller prop, the glide will certainly improve. Not that it doesn't glide, it is in fact quite good at showing where the smallest thermal is and circling lazily with the local buzzards to take advantage of it, but the drag of a stationary prop should be minimised if possible.
So, there you have it, cheap thrills in a small package.
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Last edited by JMP_blackfoot; Oct 12, 2010 at 11:27 PM.
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Old Oct 12, 2010, 03:50 AM
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Palmettoflyer's Avatar
Mount Pleasant, SC
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Very Nice!
We don't see many R/T only designs anymore. Nice work.
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Old Oct 12, 2010, 04:48 AM
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Well, frankly, an elevator would add next to nothing to the flying of this type of converted free-flight model.
I have been flying rudder-only models again recently, and really enjoying it.
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Old Oct 12, 2010, 08:10 AM
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Napa, CA
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Refreshing view of an old classic! Beautiful workmanship; thanks for sharing!
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Old Oct 12, 2010, 09:14 AM
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Saint Denis France
Joined Apr 2002
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Jean- Marie

What do you use for covering, very nice. I am loocking for something light for my next project the Lerat Bince.

If you are in the Paris region next sunday, remember, we have our 4A meeting in Persan-Beaumont @@@@

Best regards

Bernard
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Old Oct 12, 2010, 09:34 AM
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Denver, CO
Joined Jan 2004
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Nice work!
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Old Oct 12, 2010, 09:40 AM
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Oosterhout, The Netherlands
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Nice work!

Most of the sailplane's I build as a teenager in the mid seventies were rudder only. I used to build my own radio equipment from plans I found in an old book about radio controlled boats. No problems bringing her down? I do remember some bitter disputes when I wanted to go home but my plane didn't.

Should give it a try once more.
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Old Oct 12, 2010, 01:38 PM
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Quote:
Originally Posted by Dereudre Bernar View Post
What do you use for covering, very nice. I am loocking for something light for my next project the Lerat Bince.
It is a laminating film which was supplied by:

SORETRAC
214, ave. du Président-Wilson
93210 Saint-Denis La Plaine
01 49 17 57 00

SORETRAC - Rue René Cassin - Zac de la Villette aux Aulnes - 77290 Mitry Mory - France - Tél. : + 33 (0)1.60.21.71.00 - Fax : + 33 (0)1.60.21.71.17

Catherine VAZ
03 44 56 44 19
06 64 47 88 42

Film de pelliculage DRY Brillant 26µ (STC) : 9,20/100 m²
Film de pelliculage DRY Mat 28µ (STC) (25g/m²) : 14,50/100 m²

I use the matt kind, because I prefer the final appearance. I also use the same film on larger models, and dope Jap tissue over it. It makes for a drum-tight covering which looks quite convincingly good. The weight of my sample is actually 22g/m² (this includes the adhesive). It is quite easy to work with, much more so than the various ***kotes.

In the US, a slightly thicker equivalent is Doculam found here:
http://www.oregonlam.com/thermrf1.htm#1512500

Quote:
If you are in the Paris region next Sunday, remember, we have our 4A meeting in Persan-Beaumont @@@@
Bernard,

Ce week-end, je serai en Pennsylvanie avec Bob Selman au KIEF:
http://www.pafunfly.com/
Salue les copains de ma part.

Bons vols.

Jean-Marie
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Old Oct 12, 2010, 04:29 PM
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Quote:
Originally Posted by Albdag View Post
No problems bringing her down? I do remember some bitter disputes when I wanted to go home but my plane didn't.
I haven't had it in a boomer thermal yet, I mean the kind which will keep my Halftone up for twenty minutes on the glide. There is enough rudder authority to spiral the Ramrod 100 down (I hope)

Quote:
Should give it a try once more.
A small investment in time and money you won't regret, I'm sure.
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Old Oct 12, 2010, 04:46 PM
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Saint Denis France
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Jean-Marie,

Thank you very much. I live 15 minutes walking from Soretrac St Denis

Bons vols

Bernard
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Old Oct 12, 2010, 04:57 PM
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Bernard,

J'espère que l'adresse est encore valable. Celle de Mitry-Mory l'est en tous cas.
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Old Oct 12, 2010, 05:39 PM
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Rio Rancho NM
Joined Dec 2004
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Very, very nice. The last year or so I've been flying various mini FF StarDusters in the 18-22" range at a little under 30 gms. Considering the RC equipment I've got gathering dust, upping the size a bit to build something similar is an interesting idea. For that matter a PZ brick would drop right into a 22" version.

bill
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Old Oct 12, 2010, 07:59 PM
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Canada, ON, Hamilton
Joined Oct 2005
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Thanks JMP. Great looking little model. That's where all the "real fun" is.
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Old Oct 12, 2010, 09:57 PM
"Butchering Balsa since 1971"
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USA, TX, McKinney
Joined Dec 2003
1,054 Posts
I like your Ramrod, JMP..you have a real nice little ship there.

I'm with you on the inset spars, I have an Easybuilt Hornet that's been sitting in my stash of kits for 2 years because I just have a slight fear of inset spars. They are a real pain in the keister, IMHO....
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Old Oct 12, 2010, 11:23 PM
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CashRC,

A good tip is to slightly round off the edges of the spar before threading the ribs onto it. Also, try each rib individually onto the end of the spar before commiting to final assembly. Not really that difficult.
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