Newsgroups: rec.models.rc
Subject: Re: Suggestion on prop for ASP .75 ?
From: elec140@csc.canterbury.ac.nz
Date: Sun, 8 Nov 1992 08:39:26 GMT
Organization: University of Canterbury, Christchurch, New Zealand

In article <2475@rnivh.rni.sub.org>, torsten@rnivh.rni.sub.org (Torsten Leibold) writes:
> $stevee@sasb.byu.edu (Stephen Eldredge) writes:
>
>>  I am interested about your
>>model though.  I have been toying with the idea of buying the Dynaflite
>>Mustang .60.  After having built one what do you think?  Would you consider
>>doing a construction review of it for us?  It's been quite a while since we
>>have seen anything really interesting lately in this group.  (I know, its
>>different for others but hey...) In particular I'm interested in the
>>configuration of the airframe.  Is it fairly accurate in scale details?
>>Flaps? Retracts? How does it build up?  Would it be possible to mount the
>>engine at an angle so that the head doesn't ruin the profile lines?  Info on
>>this kind of stuff would be great.
>
> I'm almost about to finish the plane. So far, I'd say I'd buy it
> again, although the wood quality is not the best (the exactness of the
> die-cut parts also).
> The kit is quite cheap and there's much work to do until you are able
> to take a lokk on the raw frame. But actually that's what I wanted.
> The can be completed buy any advanced builder who has already finished
> some kits without worrying too much about the building instructions
> (cause Dynaflite doesn't provide many :-).

I've built and modified a Dynaflight 40 sized Spitfire, so thought I'd
throw in a few comments.
I second the comments about the wood and die-cutting quality - neither
are particularly good (I'd just built an Airtronics kit before the
Spit so the contrast was huge...)
It's a good kit to modify, since you don't feel bad about cutting
into or discarding a beautifully shaped kit part...

> No, the airframe is not scale at all. It has a flat bottom airfoil
> with a very strong ( <- is that right ?) thickness. The thickness
> decreases rapidly from the center to the tips. But this will make the
> plane quite stable I guess. There's no room for flaps unless you are
> willing to split the ailerons. Also, it would be quite challenging to
> install retractable gear. It is intended to mount the usual steel gear
> on a maple block which is connected to 3 ribs.

The Spitfire also has quite a thick wing, and this does make it fly
nicely. It's also not particularly scale (e.g. flat rear fuse bottom),
but does look the part in the air, especially with the gear retracted.
Typing about retracts... I added them to the Spit which is supposed
to have the wire-in-maple-blocks you described above, so they should go
into the larger Mustang alright. Having said that, to get the retracts
in I had to move the wing spar back 3/4", which meant recutting all
the spar notches in the ribs. I added extra ribs and ply reinforcing
in front of the spar to support hardwood bearers for the retract units.
Obviously the wheel wells have to be fabricated as well. I put the retract
servo in the wing centre section in front of the spar where it didn't
interfere with the aileron servo. To take the extra weight of the
retract setup I replaced the balsa wing spars with spruce and fibreglassed
the centre section.

> The plans suggest holding the wing with rubber bands (my o my), which
> I do not appreciate. I installed my own construction which includes
> two 6mm nylon screws holding the wing (that was not too difficult to
> cope with). Ah, BTW 6mm are about 1/4".

I noticed that the cutaway diagram on the Spit instruction sheet also
showed the wing attached with rubber bands. Thankfully the kit provided
dowel and nylon bolt attachment.

> Yes, you could install the engine upside down, so the head won't ruin
> the outline, but it would make handling more complicated (the plans
> doesn't mention that either) and so I installed the usual way, I won't
> see much of it in the air anyway ...

I mounted my engine upside down, and it's totally hidden within the nose
outline (except for the silencer). The plans called for mounting the
engine on hardwood bearers - I added extra ply laminations to the
firewall and used a commercial radial mount.


Over all, the kit's seem to be what you pay for - quite cheap. However
if you don't mind a bit of work in the building stage they produce good
models - the Spitfire flies very nicely indeed, even slows right down
for 3-point landings without tip-stalling.

*********************************************************
Chris Kaiser
Postgrad - Elec Eng Dept
Canterbury University
Christchurch, NEW ZEALAND

E.MAIL: kaiser@elec.canterbury.ac.nz
*********************************************************
	"When you're fresh out of lawyers
 	 You don't know how good it's gonna feel"
		- Al Stewart, 1988
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