Graupner Cirrus (the really old one!) - RC Groups
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Mar 16, 2011, 09:04 PM
Late for work again!
Gary Binnie's Avatar
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Graupner Cirrus (the really old one!)


Hello folks (yep, me again!)

I have a 1970s British 100S glider almost finished but am itching to get on with another project. I picked up two unstarted Graupner kits in January, a Cirrus and a Mini Nimbus (pretty rare find nowadays that was worth a long drive).

The Mini Nimbus is actually going to be the next project but I took a load of photos tonight of both kits and thought I should post them in case I get run over by a bus tomorrow!!

The Cirrus is quite novel with its Airfix/Monogram type plastic fuselage halves. I've read all the threads, don't fly it in freezing temperatures folks!! F3J winch launches might not be good for it either!

Must say a very big thanks to John Cole who sent me his spare instructions all the way from Arizona, I didn't realise that they were missing till I had a good look at the kit when I got it home.

The quality and completeness of both kits is on another level, seldom seen today. I don't expect to build the Cirrus for a while, possibly not even this year but here are some photos anyway. I think the kit is fairly complete, there could be some sheet balsa missing and it might have been opened just once or twice by previous owners in the last 30 years!!

Cheers

Gary
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Mar 16, 2011, 09:52 PM
Registered User
The cirrus is one of my all time favorits.Will have 2 with me at cumberland this weekend.
One has a fiberglass fuse and alerons for aerotow.You are really going to enjoy the cirrus .The cockpit frame is original.the wood is used to keep it flat when putting the
canopy on it.Looking foward to the build.
Tom
Mar 16, 2011, 09:58 PM
Late for work again!
Gary Binnie's Avatar
Seems to be a love/hate thing with these.

Afraid the build is a long way off as there is a Mini Nimbus in front of it in the build queue.

Two eh? Bit greedy?!!
Mar 16, 2011, 11:15 PM
Registered User
John Cole's Avatar
Gary,

I'll be watching with great interest as well. With enough peer pressure, you'll breeze through the Nimbus..

I believe you're right about missing a bit of balsa sheeting, but that's easy. You've got the important parts for sure.

Let me know if you have luck getting the decals reproduced, I'd like to possibly get a spare set.

My latest build is complete, and once I repair some old damages to other models, I'll get back on my Cirrus. There's really not much left to do!

Take care,
John
Mar 17, 2011, 05:34 AM
Late for work again!
Gary Binnie's Avatar
Cheers John, is that the Cirrus 75 that you were restoring?

I'm looking forward to building both of them, there are quite a few other demands on my time but that's the way it is!!

No worries for a copy of the graphics when I get round to having them done, I think it would not be sensible to try and use the originals.

From what I read fitting the optional ailerons makes very little difference to the roll rate, I can live with a poor roll rate as I'm quite used to RES types, might make it look more scale though with less dihedral, whaddya think?
Mar 17, 2011, 09:29 AM
Registered User
John Cole's Avatar
Gary,

If I were to do it again (and you know I will..) I would decrease dihedral by half and install ailerons. Yes, roll is sluggish. This can be helped by increasing ail chord by 1/4"+. (This is my intent based on current experiences).

Yes, I'm fixing up the old Cirrus 75 since I minced the original plastic fuselage. I've noticed that the Cirrus 75 uses common components to the Mini Nimbus kit you've shown on the other thread. These models might have shared production dates??

John
Mar 17, 2011, 09:35 AM
Registered User
talonxracer's Avatar
Hmm, a premade mold plug for a fuselage.......I know what I would do first.....
Mar 17, 2011, 01:57 PM
Late for work again!
Gary Binnie's Avatar
I probably will go for the aileron option when I get there, some kind of spoiler system would be nice as well, I was having a look at your setup.

Don't think I knew about the Cirrus 75 until I read about it here.
Mar 17, 2011, 03:08 PM
LSF303-AMA Fellow
tkallev's Avatar
The airfoil used on the original Cirrus did not benefit from ailerons as it was quite a slow flying model. Build it stock 2 channel and have fun.
Last edited by tkallev; Mar 17, 2011 at 04:06 PM.
Mar 17, 2011, 03:43 PM
Late for work again!
Gary Binnie's Avatar
Yep, the simple option has appeal. Should start a poll on options!

Got plenty of time to think about it.
Apr 12, 2011, 01:36 PM
Registered User
mikmerl's Avatar
I have built and enjoyed three of these gliders over the last 30 years. One was with ailerons which was a lot of work with small rewards. It flies just fine with the rudder only.

A worrisome point that I remember was that it did not like to fly fast. On more than one occasion while going up on a high start or tow, the wings would go into quite a violent flutter. Pay close attention to your glue joints during building and select a covering film that adds to the tensional rigidity of the wing panels. The best covering for this (back then) was Top Flite Super MonoKote. It really stiffens up the panels and does not sag and wrinkle with age.

I remember that the glider benefitted greatly from a bit of washout towards the tips. (you can achieve this during the covering phase) This would allow you to make slow, tight banking turns without the tips stalling.
Take heed about the antique ABS plastic fuselage, it is not only a temperature thing. The plastic dehydrates over time and becomes very brittle.
I have included some shots of mine, I could not find any of the aileron version.
I have also included a few picís of my two Cumulus 2800, it was available concurrently with the Cirrus during the 70ís. Quite expensive at the time and highly desirable (by me at least). Balsa covered foam wings and all flying stab (out of the box, the forerunner of todayís ARFís) The fuselage was a flexible molded plastic (I think polypropylene) that really absorbed the beating it took from me. I would live to get my hands on one of these again.

Sorry for hijacking your thread but reading about the Cirrus sent me on a nostalgia trip.

mike
Apr 12, 2011, 03:21 PM
LSF303-AMA Fellow
tkallev's Avatar
The Graupner Cirrus benefitted from Top Flite's Monokote (original) for the added torsional strength it afforded the open-framework wing.

tk
Apr 12, 2011, 05:40 PM
SB-28 UK Display Pilot
GeeW's Avatar
if you get to ordering some replacement decals for the Cirrus, please give me a nod as I also have a NIB Cirrus in the build queue.
Ta

Gordon
Apr 12, 2011, 06:50 PM
Late for work again!
Gary Binnie's Avatar
Great stuff Mike, not hijacking at all. There was a Cumulus 2800 for sale quite near me recently but I had to let it go (got too many models already!!). It had a Graupner power pod and NIB engine with it.

ABS ageing is a big problem with Japanese motorbike bodywork, it cracks even on bikes that don't vibrate much and is not easy to fix invisibly.

No worries Gordon, it's going to be a long time yet though, I'm trying to progress the Mini-Nimbus but things are transpiring against me to spend time on it.
Apr 12, 2011, 08:17 PM
Sink Ends Thermal Delights
Puget Sound Flyer's Avatar
I've had a Cirrus fuse and wing cores in the build queue for a couple of years now.
As I started inventorying the parts I noticed the decals were lacking in color.

After a little rcgroups searching I discovered Jim at cal-grafx.com. The decals are first rate quality and I highly recommend his service.


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