Ghost Rider 38

[Pchristy]

After winning Tobe's superb Galloping Ghost system at last year's Ponte do, I thought I'd better build something for it! I settled on a Ghost Rider 38, by David Boddington, as this was specifically designed for GG operation.

GhostRider_3 by Peter Christy, on Flickr
GhostRider_2 by Peter Christy, on Flickr
GhostRider_1 by Peter Christy, on Flickr

I've converted it to tail-dragger configuration (more suitable for the kind of fields I fly from!) and electric power (hope I have my sums right!).

All I need now is a break in the weather to test fly it!



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Pete

[iflylilplanes]

Beautiful

[tiptipflyer]

A great model for a fantastic radio, makes a perfect combo. You deserve it Pete. Well done.

Frank

[Martin]

Looks great, and I'm confident it will fly beautifully.

[Shaun]

They do fly well.
The GR was my first GG model using Tobe's actuator. It was a true international effort. Gary built and covered the airframe.
I seem to remember Glynn made one with regularly propo in as well.

[Pchristy]

Well, I finally managed to test fly the Ghost Rider today, and it was successful in that I've come back with it all in one piece, but it does need some "fettling"!

I actually managed a test "hop" a couple of weeks ago, but it was very windy, and I just flew it across the patch and landed to make sure there were no "gotchas". It lifted off OK and flew straight, but that was all I wanted to risk in the conditions!

Today was much better, with a light breeze almost straight down the runway. At full power, it leaps into the air like a scalded cat, but full down elevator is insufficient to level it off! At half throttle it cruises straight and level, but shut the throttle and it plummets downwards!

The rudder response is "adequate", but by no means excessive! The elevator is more like a trim than an actual control!

So, first of all I need to add some downthrust. I built in the recommended amount, but it clearly isn't enough. Next, I need to increase the elevator travel. I can go in one more hole on the horn, but I suspect that may not be enough. I may need to make bigger elevators!

Originally, I had intended to fit a 140 watt motor, which according to Phil's formula should have been about right for a model designed for a 1 - 1.5cc engine. However, Shaun warned me it might not be enough because of the drag caused by the wagging. Also I had trouble propping it to get close to the desired 140 watt on 3 cells, so I opted for a 200 watt equivalent. The 200 watt motor was the same diameter and only 4mm longer, so a straight fit in. On an 8x6 prop it delivers around 190 watts, which has proved to be more than adequate.

There was little sign of "gallop" on the two short test flights today. I suspect Boddo designed it that way deliberately, but it does mean the elevator control is marginal.

So, some minor tweaks called for, but showing promise!

Oh, and Tobe's radio system performed immaculately!

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Pete

[Tobe]

Very well done Pete, Galloping Ghost is basically single channel with elevator trim as it's a compromise! Remember that a Galloping Ghost actuator is a mechanical decoder where every single input has a secondary adverse input.
Would like to give here credit where it's due and that is to Phil_G that made all this possible as he gave the soul to all this!
Thank you Phil

[Pchristy]

It flies!

Still not convinced I've got the wing incidence right! Despite having jacked up the leading edge a little, I still needed some packing to get it off the deck, but the grass was quite long. I had a couple more flights from a hand launch, which seemed to indicate too much incidence.

Rudder response is good, but elevator response is next to non-existent. Its more like a trim than a control! But there is minimal "gallop", and as long as I have enough to flare the landings, I shall be happy!

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Pete

[Tobe]

Bravo.

[Twitcher]

Good stuff Peter! I've only just found this thread (not paying enough attention to MZ . . .) and found it very interesting, reflecting that it mirrors my own experiences when getting back into GG a few years ago.
It's rare to achieve a perfect GG trim instantly - it's more like pure single channel, where you have to go through a number of trimming tweaks to get the responses and flight trim you want. An example was my John Bowmer' "Swannee", which needed the wing's leading edge dropped by around 5mm, and the rudder and elevator areas increased by almost 100%! Not all in one go, either! Eventually I had a sweet-flying model that still gives me great pleasure.
Armed with this knowledge and experience, your next GG model will a lot less difficult. The only exception to this iterative trimming process was my Chatterbox. Vic Smeed somehow designed a tubby little machine whose proportions were deliberately intended to be right on the edge of what was then perceived to be feasible, but perfect for GG (the name wasn't an accident). If you ever decide to build one for GG watch out. It is HIGHLY aerobatic! Flies at a million mph, loops and rolls like a Pitts Special and glides like a brick. I love it. Mine has an aboriginal 1960-s style actuator.
GG is great fun and brings back into play a few additional skills you don't often get to use with modern propo, which makes it a bit more of a challenge.
Keep at it Peter and enjoy the ride. See you at Ponty!

David