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1/72 - DHC-1 Chipmunk by AZ model - released - new boxing in 2020


Homebee

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6 hours ago, Rod Blievers said:

Kevin K Feb 19:

 

Not to do with modelling - forgive me - but the entire Chipmunk spinning/strake issues remain often mis-understood.

 

Absolutely - agreed.

 

There can be a very significant variation on spin characteristics between individual Chipmunk airframes and the entry technique makes a big difference to the early phases.

 

Your added Australian data also contains what I think may be the key statement:

 

6 hours ago, Rod Blievers said:

"... they did tend to shorten the recovery time slightly on an aircraft normally slow to recover, but it was only a reduction in the order of three quarters of a turn in the worst case" (my italics)

 

One problem a student can have, which is invariably instructor-addressed during standard RAF (and I assume all related air arms such as the RAAF) service training, is to think that the aeroplane somehow gives you 'credit' for the number of turns you have held the controls in the recovery position. In other words, if the student has found that the airframes he has flown always recover within a turn-and-a-half and he can then recover, he may subconsciously relax the recovery action on the next one at that same point, only to find the aircraft is still spinning. At that point the recovery action will take another full-duration application to be effective and people have flown into the ground as a result of repetition of that mistake. Three quarters of a turn difference might be enough to confuse an ab initio student flying solo.

 

The Tiger Moth spin is quite steep and pronounced when compared with the Chipmunk and those Tigers I have flown have left no doubt as to spin exit - they come out with a 'bang'. The fact that the Tiger was the aeroplane which all the instructors had originally learned on might have influenced things, too. The Chipmunk is subtler.

 

Thanks for your contribution, Rod.

 

Kevin

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Very true, I remember falling into that lack of mental rigour myself at the start of early spin training, which in my case was coming on to the Chipmunk from a variety of gliders and sailplanes all of which were signfiicantly lower-energy in the spin. Also, of course, a somewhat woozy and disorientated stude can become distracted by all the whirling and slacken off the control movements just from lack of focus

 

Relatedat least some Chippies in my experience can feel as if you are on full down elevator when you still have about an inch to push. Like a double-pressure trigger.

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4 hours ago, Rod Blievers said:

Thanks Homebee, I'll do this although I'm well aware I wouldn't have the courage to invest in producing kits.

 

Also at the risk of being accused of shameless self-promotion, a Chipmunk differences article has just been posted on HyperScale. See http://clubhyper.com/reference/whichchipmunkrb_1.htm.

I found a Chippie instrument panel in one of the museums storage sheds and have been toying with the idea of

doing it up. That article of yours confirms its out of a Pommie one so that will make it easier to scrounge some bits.

Lovely little aeroplane.

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18 hours ago, Rod Blievers said:

 

T.30 was the occasionally used designation for the 60 DHC-1B-2-S5 ordered specifically by the RCAF for their service.

 

 

Rob,

 

Was the T.30 a de Havilland Canada designation?  I've not seen any RCAF document that uses the T.30 designation and was scratching my head when it appeared on the AZ box.

 

Excellent article on Hyperscale, btw.

 

Jim 

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During my slide scanning sessions, I have come across many Chipmunk pics in civvy colours and some wild schemes. I'll sort them out and do a Chipmunk dedicated post of those pics.

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Sorry gents, I've been offline for a few days now (one of many issues after a visit from TC "Debbie"), my apologies for the delay in responding

 

Navy870 - PM me if I can assist at all.

 

Airjim12 - T.30 was an RCAF nomenclature.

 

WIP - one of the great "gotchas" spinning a Chipmunk (well trying to recover anyway) was that the normally light stick forces firmed up considerably towards the full forward range because of the airflow and it's thought that several accidents were caused by a failure to apply full forward stick - because of the unusually firm forces the hapless pilot thought he'd reached the stop when he (or she) hadn't. And full forward stick is essential. I note with great dismay a recent failure-to-recover-from-a-spin accident (VH-UPD at Coffs Harbour) was primarily because the pilot had NEVER been taught to apply full forward stick.The club where I learnt to fly had witness marks painted on the stick/floor, and you were supposed to check that the marks aligned, ensuring you had full forward stick applied. Now looking down inside the cockpit at your feet whilst spinning has to be a sure recipe for airsickness!

 

KevinK - I'm not ignoring you - I'll respond shortly.

 

Cheers, Rod.,

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Kevin K - not for one second is this intended to be an I'm right/you're wrong response, but isn't it fascinating how we've interpreted that sentence quite differently?

 

Given that students are taught to positively apply and maintain anti-spin control inputs, I've always taken the "three-quarters of a turn in the worse case" as meaning that DCA weren't greatly impressed by the effectiveness of the strakes. In the UK now you can't fly ANY Chipmunk without strakes, yet here you it's never been a requirement. As an aside, I learned to fly in Chipmunks that had the narrow-chord rudder and no strakes - I don't think then (1961) I'd even heard of those strake thingies!

 

Bill Fisher (he of encyclopedic Chipmunk knowledge) told me that, after a series of fatal RAF Chipmunk spinning accidents, questions were being asked in parliament and thus the MoD felt compelled to do something (anything) about this.  The strakes were the simple/quick answer. Interestingly, the accidents all occurred at UAS's where the previous equipment had been the much more benign (specifically with spin recovery) Tiger Moth...

 

Cheers,

Rod.

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Rod,

 

I fully agree - it's not a terribly good reason to modify the aircraft if no-one else is having the problem, and all aeroplanes I have spun have characteristics which vary from airframe to airframe. There are so many variables and when we add in variations in spin entry technique, plus (these days) student/instructor emphasis often being put on recovery from the very early stages of a spin, many low--time student pilots won't have had the experience to understand what's going on as the spin varies.

 

Unfortunately, as all my Chipmunk flying was done on UK-registered aircraft, I've not flown one without strakes to compare it.

 

Your last paragraph is absolutely true - my Father told me the same thing. Interestingly, the Tiger itself acquired strakes around 1942.

 

All the best,

 

Kevin

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Hi Kevin:

 

But I think the Tiger's strakes were to prevent spin entry, making them true "anti-spinning strakes".

 

My own Chipmunk has strakes and the broad-chord rudder (it's a 1994 RAF retiree), but I have in recent times spun a Chipmunk with no strakes/broad-chord rudder and one with no strakes/narrow-chord rudder. The lack of rudder authority in general was apparent with the latter aircraft, but they both seemed to enter and recover much the same.

 

Your comment about the variables about each aircraft's handling reminds me that on some aircraft, once the correct inputs are applied, the spin rate will initially increase before recovery.  Seeing this, I can well imagine an inexperienced pilot relaxing his inputs at that point, which won't help him at all! It's another Chipmunk "gotcha"!

 

Despite my skepticism towards the effectiveness of the strakes, I confess that I would never entertain removing them!

 

Cheers,

 

Rod.

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  • 3 weeks later...

Weeeelllll, with the current Gov't, 'mess' isn't far wrong; oops no politics, OK guys forget what I said!!!

I have pointed this out to Jan on 72nd A/C in our AZ/KP news thread, no reply yet but we know he reads it so we wait & see.

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Released:

 

- ref. AZ7556 - https://www.azmodel.cz/produkt/dhc-1-chipmunk-t-10/

 

AZ7556_box.jpg?resize=768,540&ssl=1

 

- ref. AZ7557 - https://www.azmodel.cz/produkt/dhc-1-chipmunk-t-20/

 

 

AZ7557_box.jpg?resize=768,549&ssl=1

 

- ref. AZ7558 - https://www.azmodel.cz/produkt/dhc-1-chipmunk-t-30/

 

AZ7558_box.jpg?resize=768,543&ssl=1

 

- ref. AZ7559 - https://www.azmodel.cz/produkt/dhc-1-chipmunk-t-10-with-lycoming-engine/

 

AZ7559_box.jpg?fit=1024,724&ssl=1

 

V.P.

Edited by Homebee
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Having built one, the proportions of the RAF decals are wrong - red centre is about 1mm indersize on the 12mm wing decals. Blue should be 12mm dia, white 8mm dia and red 4mm dia. It looks better once you use aftermarket roundels.

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Nigel - regarding the roundels, there's another (often overlooked issue). The fuselage roundel was originally 16" diameter, but was changed to 18" in the early 1970's (with the advent of the second R/W/LAG scheme?). It doesn't sound much but it's obvious when you compare photos...

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