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Tiger Moth by Value Planes


Geoff Daunt
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  • 4 months later...
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  • 3 weeks later...

Hi Nigel,

The engine is a "Gipsy" version of the Laser 200. The climb was very slow on just the one cylinder but she was stable and controllable and didn't stall. On both cylinders the engine pulled 7100RPM, and on the one 3600 RPM

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7 hours ago, Ady Hayward said:

Hi Nigel,

The engine is a "Gipsy" version of the Laser 200. The climb was very slow on just the one cylinder but she was stable and controllable and didn't stall. On both cylinders the engine pulled 7100RPM, and on the one 3600 RPM

Hi Ady

 

Mine is the Gypsy as well going in a Miles Hobby Hawk when I get my mojo back, we are in a club of 3 I understand.

 

5 hours ago, Simon Chaddock said:

I note the "Gipsy" Laser 200 goes the right way round, clockwise when viewed from the front, and thus matches the scale offset cowling air intake. .

A rare combination or is that just a "show" prop?

Simon that is correct, the ‘Gypsy’ version so named as it turned in the same direction as the full size, reverse of normal model engines.

 

I ordered the Fiala props from Bernie at Jeti UK you can order their props in reverse rotation so have a selection to try.

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Nigel

Some 25 years ago I hand swung a Gipsy Major in a Tiger Moth many times and that 78" prop looks enormous when you are standing close in front of it.

At least the starting "impulse" magneto has slightly delayed timing to reduce the likely hood of a back fire ripping the prop out of your hands. Technique is everything.  .  

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2 hours ago, Simon Chaddock said:

Nigel

Some 25 years ago I hand swung a Gipsy Major in a Tiger Moth many times and that 78" prop looks enormous when you are standing close in front of it.

At least the starting "impulse" magneto has slightly delayed timing to reduce the likely hood of a back fire ripping the prop out of your hands. Technique is everything.  .  

Oh yes, I was taught that many years ago, when  first did it I felt it was like hand feeding a tiger! But once I got into the swing (pun intended) of it I was ok. As you say technique is everything.

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On 14/04/2025 at 15:59, Ady Hayward said:

Hi Nigel,

The engine is a "Gipsy" version of the Laser 200. The climb was very slow on just the one cylinder but she was stable and controllable and didn't stall. On both cylinders the engine pulled 7100RPM, and on the one 3600 RPM

Hi Ady,     

Did you determine the cause of the dropped cylinder? I can only imagine how marginal the climb was!

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15 hours ago, David P Williams said:

Hand swung many Austers, Tiger Moths, Stampes and Chipmunks. Scariest was the 450hp Pratt & Whitney engined Stearman with an 8ft plus prop.

I found the Tiger Moth okay to hand swing - with the aeroplane in the tail dragger attitude, and 'British' rotation direction, you pull through and naturally turn away. A J3 Cub I found OK, despite the opposite rotation, and a Rotax powered AX3 microlight.

Tricycle gear Cessnas and Pipers with American engines- ugh. I found the height of the prop, coupled with the direction of rotation just 'wrong' - you naturally lean towards the prop arc. They also have metal props with sharp trailing edges - you have to curl your fingers round the blade to have enough grip - I hate the thought of what might happen to your hand if the engine does kick back. 'It won't kick back as long as you start on the impulse mag only' they say. Yeah, right. I've had enough engines kick back during normal electric start, which is on the impulse mag only, not to trust that. I'd rather have a cup of tea and wait for the battery cart.

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  • 1 month later...

The Tiggie has flown again and with the engine pulling on two cylinders proved a bit underpowered. Pulling 7100 rpm on a 19x6 Xoar prop the climb was safe albeit slow and looked good on 2/3 thottle but could not loop even with a good dive first. I decided to swap the Laser for an OS GF40 and saw a big improvement in climb rate and can pull a loop with a gentle dive first.

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That’s interesting Ady. I would have hoped the 200i would be adequate for a ¼ (ish) scale Tiggie.

What is the weight of your model? I’m building a low wing model and have a 200i to go in it. The expected weight is 26 or 27lbs so if your findings are anything to go by, the Laser could be well under-powered for the model, something I’ve feared for a while.

I’ve considered the new Saito FG50 but am put off by their carbs, they tend to airlock and stop. Morris Mini Motors recognised this a long while ago and made Walbro conversion sets, I bought one for a FG30, it solved the problem but added over £200 to the price.

The OS GF40 has a modified Walbro, how reliable have you found that? Also, the OS has a sticky-out silencer, did that fit in the Gipsy cowl, or did you perhaps get something made up?

I apologise for the questions, but your findings are a bit concerning.      

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10 hours ago, Ady Hayward said:

Pulling 7100 rpm on a 19x6 Xoar prop

 

That is pretty poor as i would expect that sort of rpm from 20x6 props. If you were still running the 2.5 turns you mentioned earlier its likely the engine was very rich, although at 2.5 turns i would almost be surprised the thing ran at all. 

 

How heavy did the model end up?

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I have the Saito FG-30 it does gargle on take off but after that it never misses a beat, I also have the Saito 180, I put a Rexel ignition and a saito spark plug in it, and as stated on Rcgroups, it does run well on its original methanol carb.

 

 Whats a modified Walbro ?

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Sometimes the Saito would miss a beat and then continue running, at other times it would stop, Their recommendation (included as an addendum sheet with the manual) was to tip the model on its side after starting to clear the airlock - hardly a practical solution in a largish model.

 

OS are not specific about the carb, only that it has been developed in collaboration with Walbro. I believe Saito said a similar thing at one time but their carb didn't look anything like a Walbro.

 

Hopefully Ady will provide some clarification. 

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The Tiggie weight is 12.9kgs and is a very draggy airframe hence my choice for a finer pitch. The engine was running cleanly and each cylinder was leaned to a rpm drop and backed off 1/8 turn.

The GF40 and silencer fitted within the cowl ok after fitting of an OS elbow exhaust fitting which was added allowing the silencer to be turned behind the engine. It does need a starter to achieve sufficient rpm to allow ignition as there is a minimum 120rpm needed. It was running slightly rich but clean and using an oil ratio of 1/30 on a 19x8 prop for the flight, and flight performance was noticeably improved over the Laser 200. I have another project in the wings for the Laser 200 so it will fly again.

 

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Posted (edited)

I agree with Jon that your revs of 7100 for that size / make of prop is well below what it should, and can be. Neither of my 200 inlines perform that badly!

 

This is my Hurri being flown un scale like, weights in at the same as your Tiggi and even with it being less draggy than the Tiggi it just shows how these engines can perform. The prop is an 18x8 APC.

 

Your Tiggi is more like my Stampe in terms of weight and drag and that is powered by a 180 on a 20x6 which is more than adequate. Having flown models back to back after changing engines over I can say that the 200 inline outperforms the 180.

Edited by Ron Gray
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4 hours ago, Ady Hayward said:

backed off 1/8 turn

 

theres no need. peak rpm then go for it. 

 

Is it really 28lbs? That seems extremely high for a 1/4 tiger. I know there is loads of detail but im surprised its that high. I would still expect the 200 to fly it though and i would use a 20x6, but i suspect performance would be scale and nothing more. 

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Posted (edited)

Sorry John I’ve forgotten and I didn’t record it anywhere! The ground running on the Hurricane and the tuning / rev checking were done over a year ago but as you can tell from the vid it isn’t running slow! (Just realised that the vid wasn’t published in my previous post).

 

 

Edited by Ron Gray
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