Chipmunk Mk.23

[DaveUnwin]

Hi All, I'm writing an article about flying Chipmunk Mk.23 Tango Fox/Bumblemunk and would welcome any info on it. Does anyone know why it was only in the RAF for a few years? Also, does anyone know anything about Farm Aviation? What happened to the other Mk23s? Cheers, Dave

[DaveReidUK]

Its first civil owner was the RAE (Farnborough) Aero Club, so maybe some kind of under-the-counter transaction ?

[Allan Lupton]

Farm Aviation of Rush Green, Hertfordshire (just South of Hitchin/West of Stevenage) was a crop-spraying outfit. Bill Bowker was the man behind it, I think, and they certainly had a Chipmunk of that reg.

[DaveUnwin]

Thanks Dave & Allan, all useful stuff. Interesting that it clearly still has a Gypsy engine - as a sprayer I'd assumed that part of the conversion was to fit a better, more powerful engine.

[DaveReidUK]

Originally Posted by DaveUnwin

Interesting that it clearly still has a Gypsy engine - as a sprayer I'd assumed that part of the conversion was to fit a better, more powerful engine.

If I'm not mistaken, in the photo in post #1 it has a Lycoming O-360, whereas in the earlier B&W photo it still has the Gipsy Major.

[VictorGolf]

I like the elastic bands holding the u/c fairings on.

[DaveReidUK]

Originally Posted by DaveUnwin

What happened to the other Mk23s?

G-APMN C1/0128 ex WB680 w/o at Potterhanworth Fen 27/5/1958
G-APOS C1/0763 ex WP893 to N8345 8/1969, current as N40291 with Lycoming GO-480
G-ASPW C1/0602 ex WK580 (composite, with parts of C1/0193 ex WB746) w/o after hitting cables at Wheathampstead 1/7/1967
G-ATVF C1/0265 ex WD327 current, based at RAF Halton
G-AOTF C1/0015 ex WB563 current with Lycoming O-360, based at Saltby

The first two were DH conversions; the other three were converted by Farm Aviation.

[DaveUnwin]

Originally Posted by DaveReidUK

If I'm not mistaken, in the photo in post #1 it has a Lycoming O-360, whereas in the earlier B&W photo it still has the Gipsy Major.

That's correct Dave - I'm flying (well, between tows) in the first pic, it does have a -360. Thanks for the info on the others.

[Allan Lupton]

Originally Posted by DaveUnwin

Thanks Dave & Allan, all useful stuff. Interesting that it clearly still has a Gypsy engine - as a sprayer I'd assumed that part of the conversion was to fit a better, more powerful engine.

Wikipedia suggests "Chipmunk Mk 23 Five converted T.10s powered by de Havilland Gipsy Major 10 Series 2 engine and with agricultural spray equipment."
without putting a date to it. Whether the Gipsy Major 10 Series 2 or the Lycoming O-360 is the "better" engine is not for me to say, but they were 145 b.h.p. and 180 b.h.p.

[DaveUnwin]

The O-360 is lighter, more powerful and more reliable - and uses a LOT less oil!

[Kemble Pitts]

... but ruins the lines of originally pretty aeroplanes.

[DaveReidUK]

Originally Posted by Allan Lupton

Whether the Gipsy Major 10 Series 2 or the Lycoming O-360 is the "better" engine is not for me to say, but they were 145 b.h.p. and 180 b.h.p.

Or try a 275 hp GO-480.



Interesting that the US owner has restored this Mk.23 to the original Chipmunk tandem 2-seat configuration. Shame about the rudder.

[Kemble Pitts]

Nice, so now he's b**ggered both ends of an otherwise pretty aeroplane!!!

[DaveUnwin]

Originally Posted by Kemble Pitts

... but ruins the lines of originally pretty aeroplanes.

Hmmm. So the choices are that you could have an aeroplane fitted with an engine that is lighter, more powerful and more reliable, and uses a lot less oil, or alternatively you could have an aeroplane fitted with an engine that is heavier, less powerful, less reliable, and uses a lot more oil, but is prettier. Sorry, I place power and reliability above pretty.

[oxenos]

Sorry, I place power and reliability above pretty.

Does your wife/girlfriend read this???

[Allan Lupton]

My inclination is to prefer originality when dealing with out of date machinery rather than post-period redesign - in my case it's cars, but I think/hope most owners of old aeroplanes take that view. For example, would you re-engine a Spitfire with something more powerful than and a different shape from a RR Merlin?
The de Havilland Gipsy Major engine is quite common and has a good support for overhaul, etc.

[megan]

Australia has its share of Chippie mods.



Sasin Aerostructures SA-29 Spraymaster: Photo Geoff Goodall

SA29 Spraymaster. The original engine was swapped out for a 210 hp Continental, although a Mk 2 version was offered with a conventional 145 hp Gipsy Major 10. The aircraft above was the Sundowner (non agricultural) variant featuring a 180 hp Lycoming O-360 engine: Photo Ed Coates

[DaveUnwin]

With regard to a Spitfire of course not Allan, but TF works, and sometimes works hard. The O-360 is a better engine from every perspective, which is why they junked the Gypsy. I flew a Beagle Terrier last year that had had the same conversion - nicest Auster I'd ever flown!

[Jhieminga]

Originally Posted by Kemble Pitts

Nice, so now he's b**ggered both ends of an otherwise pretty aeroplane!!!

I agree that it doesn't do much for the Chippie's lines, but with almost double the horses up front, I'd want a larger rudder and fin too!

[sycamore]

Dave /Allan ,the Allison V1710 could be a replacement for the Merlin,in Spitfires,one in USA and one in France,both replicas,but not here,I fear..!
The picture of Farm Aviation G-APOS in the video shows it has `slats`fitted on the outboard wing section;anyone know if this was `deH mod ` ,or FmAv…?
Difficult to tell if `OTF` had them fitted as well....