DHC-1 chipmunk

[dragontech]

hi gentlemen i know some of you out there own the above type of aircraft, i am looking for a repair manual illustration of the rear fuselage skinning i am in the middle of starting a new profile but no drawings match up to the photos, everything else is working out fine just that last section of fuselage that carries the tailplane, here is a sample of my work..

[Planemike]

I see no DHC-1 Chipmunks.....!!! Be helpful to have some capitals in the scrip, makes it a lot easier to read. I guess your keyboard has a "caps" key. Just a comment.

Oh, I should have said.... "Welcome to the forum !!!"

[NutLoose]

If no one can help here, register and ask on here too,
Historic Aviation

Welcome to the forums

[Arclite01]

Try DH Support - I expect they have drawings

de Havilland Support Ltd

Arc

[megan]

Do any of you have experience with spinning the aircraft both before and after the introduction of the spin strakes? Interested in the change in characteristics. Flew them without the strakes and seemed to have no problem, providing recovery was done by the book - never tried experimenting to prove the veracity of the book mind.

Likewise with the Tiger Moth, never flew one with strakes, and never had a problem. Perhaps Danny42C may be in a position and able to comment on the Tiger. Strakes were never adopted on either type here in Australia.

[binbrook]

Flew it with both the original rudder and the long-chord rudder as a student (pupil then), and with strakes as a QFI - I don't recall that spin entry and recovery differed much. Does anyone recall the incidents which prompted the mods?

[air pig]

Like the Pembroke, a most unlikely spy-plane, sorry thread drift.

[Basil]

Originally Posted by megan

Do any of you have experience with spinning the aircraft both before and after the introduction of the spin strakes? Interested in the change in characteristics. Flew them without the strakes and seemed to have no problem, providing recovery was done by the book - never tried experimenting to prove the veracity of the book mind.

Likewise with the Tiger Moth, never flew one with strakes, and never had a problem. Perhaps Danny42C may be in a position and able to comment on the Tiger. Strakes were never adopted on either type here in Australia.

I recollect (could have been on Prune) reading an account by someone who sat there and flew up to, IIRC, about 10,000ft and spun it down. After a quite a few turns it went flat and took a long time to recover
Not sure if it was pre or post strakes.

[ancientaviator62]

My fallible friend AKA my memory seems to recall that the strakes were fitted to the Chippy after a problem with spin recovery on an a/c with a rather aft c of g.
Can anyone confirm (or refute) this ?

[Miles Magister]

Spun them for 8 turns with the strakes fitted, all as advertised and no problems.

[Dan Winterland]

The strakes were fitted as a result of some early spinning accidents soo after the Chippy entered service. At the time, the standard spin entry was done from a stall and there was a standard spin recovery used on all types. This was less than 100% successful on the Chippy and as a result the stakes were fitted (Similar strakes were fitted to Tiger Moths). These act as spoilers at high angles of attack and re-energise the airflow and spread it out a bit which made the rudder more effective thus aiding recovery. At about the same time, the wide chord rudder was fitted. But this was to aid control during aerobatics and not for spin recovery.

Also, the entry and more importantly, the recovery was modified. The entry was now not done from the stall, but from a reinforced entry made using full pro spin controls from 50 knots. The new recovery introduced a pause after the application of rudder - the usual technique was to count to two bananas. In addition, it was noted that there could be a null point in the elevator feel which made moving the stick forward more difficult past neutral. This is why there is a placard in civilian Chipmunks which mentions that the column may have to be moved all the way forwards.

This entry and recovery works fine and in about a thousand spins in the Chippy using these, I have never had an issue. I have also entered spins from the stall, and these are very different. They are flatter, slower and take longer to recover. I suspect it is in this spin that the strakes are designed for and recovering a strakeless aircraft in this event would lead to using far more heartbeats. I have spoken to pilots who have spun strakeless Chippys and they say there is no discernible difference - but I suspect they were using the 'new' techniques.

Spinning and aerobatics are prohibited on the strakeless aircraft in the UK and Australia - and I think NZ as well.

[rjtjrt]

Spinning Chipmunk has been a topic of conversation many times over the years.
I am no expert.
There is an excellent article on Chipmunk spin recovery, from Australian Safety Digest No 22, (our crash comic that then was superb).
It is available in this fairly recent report (as an appendix, starting on page 22 - 27 of this report - "The Chipmink Spin - The Facts"

https://www.atsb.gov.au/media/576808...nal_report.pdf

My take on it is all Dan Winterland said, espec about being sure stick if really fully forward.
Additionaly know it can take quite some time to recover from spin even with proper technique and control position, and do not be tempted to think proper recovery technique is not working for some reason, but just keep the controls in recommended position and WAIT (do not think you have to try something else as "it is not recovering").

Again, the appendixed Spin article above is seminal and well worth reading a couple of times if you fly the Chipmunk.

Edit, more here:

http://www.pprune.org/pacific-genera...-accident.html

[rugmuncher]

Originally Posted by Arclite01

Try DH Support - I expect they have drawings

de Havilland Support Ltd

Arc

Viking Air are now the holders of the Type Certificate.
Viking Aircraft | Viking Air Ltd

[Quietplease]

The strake mod made it out to MEAF in 1960 so that was probably a year or two after the rest of the RAF.
May 25th 1960 in WZ884 I, accompanied by a young J T S Lewis, did the post mod airtest. Don't think we found much difference.
The only problem was that F.O. Neil Williams complained he could only get a 360 flick on the top of a loop rather than 540 pre-mod. Probably a good thing as the top wing surface went rather crinkly doing that.

[Dora-9]

I suspect it is in this spin that the strakes are designed for and recovering a strakeless aircraft in this event would lead to using far more heartbeats.

Hmm. Having once frightened myself witless by losing control during an upward climbing roll manouvre (stupid I know) in a strakeless Chipmunk, I'm not sure I'd care to repeat the manouvre in an aircraft fitted with them to see if there's a difference! For the record., the aircraft violently tumbled itself into a flattish spin, and it took me several seconds to catch up with what the aircraft was doing.

But I think Dan is (as always) absoltutely correct when he talks about the difference between a 50 kt deliberate entry and a inadvertent stalled entry. This is alluded to in the VH-UPD Accident Report - Investigation: AO-2014-114 - Collision with terrain involving DHC-1, 'Chipmunk' VH-UPD near Coffs Harbour, NSW on 29 June 2014

The circumstances of a spin entry near the top of a loop may be very different. If a loop is not carriedout correctly,the aeroplane can flick-roll or stall at the top of the loop and, if not in balanced flight,may enter an upright spin.

The whole report is well worth reading. The inadequate training the hapless pilot had received makes me angry every time!

[Mandator]

Rugmuncher: Viking Air is only responsible for the Canadian-built variants. DHSL holds the reigns for the remainder of the 1,000 UK-built aircraft and, I suppose, the remaining Portuguese licence-built examples.