The "Galloping Ghost" Handbook

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Tobe
Posts: 665
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: The "Galloping Ghost" Handbook

Post by Tobe »

The issue is that if voltage drops you have to trim down and in turns you get elevator down. Guys flying aerobatics were accepting this...with this configuration some were able to fly inverted and make attempts on a bunt.
If for whatever reason the actuator stopped failsafe is full elevator up...determalizer?...but absolutely no glide condition.
Today with BEC and constant voltage it wouldn't be a big issue as it was.
We have also to remember that most models were basically rudder only with some elevator assistance and throttle control was not distinct as today when you fly electric/separate servo, most setting in the old days gave you 3-5 positions for throttle.
Rudder authority would remain the same in either choice as both would decrease with voltage drop but with "inverted " you have to trim down instead to give trim up, a standard GG Rand have on the total trow about 2/3 up and 1/3 down.
If you flew with a cage or the Controlaire actuator instead you got about the same up as down but were still voltage dependent.
It's all a matter of geometry and voltage on Rx pack.
I used to fly a X-103 this way at the expenses of a fresh battery pack for each flight and after 3-4 minutes you would start noticing so at the end I switched to conventional setup, probably I wouldn't have done it if it was electric and had a nice BEC.
Last edited by Tobe on 11 Sep 2021, 17:55, edited 1 time in total.
Cheers,

Tobe
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Shaun
Posts: 1049
Joined: 15 Feb 2018, 21:49
Location: West Yorkshire

Re: The "Galloping Ghost" Handbook

Post by Shaun »

As Tobe said 😁😁😁
Martin
Posts: 744
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: The "Galloping Ghost" Handbook

Post by Martin »

Thanks. I hadn't considered the effect of decreasing voltage as the battery discharges - my g.g. models are all electric. I have powered some of my actuators not via a BEC, but instead from the 2-cell LiPo main battery - with the decoder doing PWM to limit the motor power - so they will have seen a falling voltage during the flight, but I guess not as much as in the old days using DEACs or primary cells. :)

In any case, all my models are the correct 'slow pulse for up', type - it was just that after flying them, I thought 'slow for down' would give just as much control.

The failsafe argument seems wrong though - surely with the actuator unpowered and self-centred, you get down elevator, not up? I would have thought that full-up would be a (slightly) safer fail safe setting than full-down, on the type of model typically flown by g.g. I guess better turn trim was the overriding reason for the standard choice.
Tobe
Posts: 665
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: The "Galloping Ghost" Handbook

Post by Tobe »

.....with full down the model will not fly away! It was the belief of those day.
You will see the same for example on old Bonner linear servos.
Cheers,

Tobe
AlexC
Posts: 53
Joined: 22 Feb 2018, 21:03

Re: The "Galloping Ghost" Handbook

Post by AlexC »

If anyone would like to have the book drop me a message with your address.


Alex.
jmendoza
Posts: 167
Joined: 18 Feb 2018, 23:07

Re: The "Galloping Ghost" Handbook

Post by jmendoza »

Thanks for posting the GG manual!

Lotsa relays and tubes in those original GG sets. It must have been real tricky to adjust the trim with those bird cage linkages. The Rand, Go-Act, and Controlaire Ghost actuators must have been quite the advancement as they had control arms and used pushrods and control horns so trim was much easier to tweak. I'm amazed that the original systems worked at all! It is hard enough to trim and fly the newer systems using Phils recoder, an ESC, and a Tobe actuator.

Some things are no longer an issue, especially flying electric with a BEC equipped ESC; no more elevator trim changes due to battery voltage dropping, and no full up on throttle changes with the Tobe.

I can only imagine what would happen if you used fast pulsing for up, it would be quite the challenge when doing hard turns. Plus, if you lost signal, the plane would fail safe and nose right into the ground!

Guys used to put a reversing bellcrank on the elevator linkage for planes that could not have the control horn on the bottom of the elevator. A 120 degree bellcrank gave you more even up and down with a Rand and reduced the full up on throttle.

Ed Rutherford(RIP) made that Rand GG demo rig and video and inadvertently put the control horn on top of the elevator. It was just a demo however so it did not matter.
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