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Miss Deeds or 1/4 semi scale Cassutt

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Erfolg17/09/2019 14:31:12
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Nigel

The use of Blue Foam is certainly not a new idea. Perhaps the most well know is Chris Golds, who would PVA the finished form.

In my case I use 1.5 oz Glass Cloth, it makes for a much better finish and dinge resistance. I mainly just use one layer although I have been known to use two, applied together.

My technique is to mask the balsa area, with masking tape. I then lay up onto the tape with a slight overlap. In the case of the Cassutt I did the whole tip in one go, as the cloth draped over it very well. I apply about 4 coats of WBV, having left the first coat for a few hours, then rubbed down slightly. In this case it was not really needed. The next 3 I do when touch dry, about 30 minutes although an hour is probably better. When dry, leaving overnight. I just trim through the cloth into the balsa end rib. Then I just peel of the masking tape, together with the glass overlap.

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I perhaps should have shown the template I use to form the nose. Again not rocket science, although in this era, where very few build, the methodical stage by stage approach in obtaining acceptable accuracy is not as commonly known.

I believe that the secret to the accuracy that good tradesmen achieve, is more to do with a systematic approach, rather than just an inherent skill that revealed itself when they picked up the first tool

Nigel R17/09/2019 16:21:36
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a systematic approach - otherwise known as doing a proper job, i.e. avoiding anything remotely like a bodge

works wonders in many areas of life

thanks for sharing the tip technique - must try this

Erfolg17/09/2019 16:32:03
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This is perhaps an extreme example of using blue foam then glassing it.

x1.jpg

paint2.jpg

If you look at the tail pipe you can see the blue foam still. I must admit that i did not try for a good finish, as the full size was very rough, in all aspects.

paint1.jpg

Erfolg19/09/2019 11:12:11
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Well, Whilst some bits are drying, I thought now is a good time to show the next stage. As I was pressed for time (I have only the one).sad

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For this model I made some stick on templates. The top of the turtle back remains the same as the PM plan, as is the bottom. It is the shoulder area that I widened to a more scale dimension, of the narrowest reference I found, whilst reading and searching about Cassutt builds.

I was tempted to produce a more rounded top, to the turtle back, as it appears that most if not all full size have a bent piece of ply wood in this area. In the end I decided to keep things simple as the PM drawing.

In my opinion it does indicate what you can do to many of Peters semi scale designs, although at our own risk.

Rather stupidly I have removed the uprights from my body jig, as they were getting in the way of checking the tailplane to wing alignment.

This is what it would have looked like although in this case a TH Clean Sweep.

Perhaps I should mention there is another slight deviation from plan, in that I intend using a plate type undercarriage , as per full size. On that basis I have a ply section in the base a little wider than Peters, and some ply spreader plates on the inside to distribute the forces a little differently to Peters Torsion Bar arrangement. I do find that torsion bars work really well. My oldest model at 40 years old has them and flies most weeks.

mm4.jpg

Th real thing now!

cassutt iiim racer - untitled _ aviation photo #1621078 ___.jpg

As you can see this version has something similar to a torsion bar set upcrying

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and one with a broad chord UCsmiley

Edited By Erfolg on 19/09/2019 11:26:21

Erfolg23/09/2019 14:03:52
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Right then, the body has been pretty much finished, in most respects.

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I did intend making a Fibre glass UC, just have not got around to it.

Will the Aluminum one do, probably not, as I am not sure of the grade, 99% certain it is not a precipitation hardening type, as they do not seem to popular as they were. Silicon Aluminum being very cheap, and does most things that manufacturing wants. Although its strength and resistance to permanent deformation is low.

The other major clue, I bent it cold, no heat treatment and even now there are no intergranlar cracking or even orange peel affects.

The Cheeks are a little bigger than PMs, just a minor detail. Look at enough pictures and you conclude there are no standard cheeks , in shape or size. So you can pick what you want, or even do your own thing, it probably will be neither totally right or wrong.

Nigel R23/09/2019 15:24:28
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Looking good erfolg yes

Martyn K24/09/2019 15:58:18
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Yes - it looks very smart indeed

Erfolg26/09/2019 15:21:34
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Nearing the end of basic construction.

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The next bits are the time consuming end of things. Sorting out Lipo storage, fitting servos and linkages. It is after fitting all the gubbins that it becomes clear if lead is needed. The plus side is the wing area is generous.

For power I will be fitting a Turnigy D3836/8 motor, running of a 4s Lipo. I know from previous experience that these motors are good for 480 watts. I also have one!

With this model there is space to get stuff in, the PM small Cassutt was a squeeze as an electric.

Edited By Erfolg on 26/09/2019 15:22:37

Peter Miller26/09/2019 16:30:21
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I hope that you have a contrasting colour underneath

Erfolg26/09/2019 19:03:31
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The answer is nosmiley

cassuttoutlaw.jpg

I will probably finish similar to this

Peter Miller26/09/2019 20:49:20
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Looks Good

Erfolg29/09/2019 11:39:55
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No flying today it would seem. At least the weather was not to bad yesterday, and i got into the garden.

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These pictures show the relative size of both PM Cassutts.

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I am running the Cassutt on 2 *4s *2200 Lipos "Y" leaded together. The convention general term is a 4s * 4400,

The first flight has the CG @ 20% ahead of the 25% that Pete has on the plan. This is to be absolutely sure that there will not be any pitch issues. The small Cassutt was flown @ 30%, my test pilot has never forgiven me. relocated at 25%, it is a pussy cat. Being small I never let it get far from the field.

Erfolg03/10/2019 14:07:12
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Yesterday there was a brief weather window, in that there was little wind , nor rain. It did not last long however.

The Pm big Cassutt has now had its first flight, flown by an experienced flier, who frequently flies at model air shows, also flies jet, ducted fan and those very large aerobatic model aircraft. In short much more accomplished and knowledgeable flyer than myself. My usual pilot not being available whose experience is towards larger scale models, schedule aerobatics and scale gliders.

Onto the the Cassutt, the model has more than enough power to get of our grass strip. Flies true. Accomplishes vertical climbs without screwing out or needing correction, the stall has no wing dropping, with the forward CG is a mush.

At the 3 minute point the model lost power, to the extent that the landing was dead stick. Again not a real problem, other than the lack of height at the time. The model made the strip without any excitement or poor behavior.

The dead stick came as a surprise as a conservative estimate in excess of 8 minutes had been made (by me) with the timer set at 6 minutes.

Also the model spent much of its time at half throttle, maintaining a respectable speed.

At home a check of the Lipo charge indicated that there was circa 70% not used.

In most aspects the first flight was a success, in that the model is of a really good design. However there is a power train issue, not relating specifically to the model, in all probability. Further garden testing will now commence.

Edited By Erfolg on 03/10/2019 14:08:34

Edited By Erfolg on 03/10/2019 14:09:19

Peter Miller03/10/2019 15:17:33
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Glad to hear that you are happy with the flight performance.

My power train was was follows. 3541 1070 motor, 4 amp ESC, 11X5.5 APC prop, 3S 3300 battery. Lasted about 8 minutes if I remember correctly

Edited By Peter Miller on 03/10/2019 15:17:54

Nigel R03/10/2019 17:14:33
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Erf, sounds like an overheating problem.

You might need to add a lip to the cooling exit hole to encourage the flow, or similar.

My midwing Aerobat suffered this same issue (although no cutouts, the ESC was simply quite toasty when I landed and tried putting a finger on it) - the cooling exit hole was underside of fuselage just behind wing. I put a simple ramp on the inside to encourage more of a venturi effect, which solved the problem for me.

Good to hear the positive flight report. My dad has just started building one of these.

Edited By Nigel R on 03/10/2019 17:15:24

Erfolg08/10/2019 16:42:59
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Well Nigel, you are so right, go to the top of the class.smiley So right in fact that the motor burnt out at approximately 4 minutes of static running at full power.

Ah, the small of burnt Shellac, it is almost artistic, the glint of copper amongst a sea of black.

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Now this affect is beloved of up-cyclers, normally done with a poker that is heated to red hot i am told. In this case just the application of electrons.

The problem was due to a cowl that had both an inlet and outlet, unfortunately there was a built in blockage in the middle.

As the model carried a chunk of lead behind the motor to obtain the 20% CG, a heavier, more powerful motor has been purchased..

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This the initial mounting of the motor and lead.

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This picture shows some of the lead having been moved into the cowl. Far more significantly the passage into the cowl has been completed, previously a silly boy forgot to make the passages.

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To ensure that the motor actually benefits from the air movement, a baffle has been inserted in the cowl, with is intended to be a minimal gap.

The set up was run for 6 minutes on the ground. No direct measurement of the motor was possible, without removing the cowl. An indirect means of estimating was substituted of grasping the ally spinner. It was pretty much stone cold.

The model has another outing again in a weather window. Flown by the second test pilot. His estimation was that the model was a pussy cat. Not lacking in power, achieving a short take off run. Stall, non existent, good roll rate, combined with harmonization of aileron to elevator, that rudder is not needed in turns. After 6 minutes the model was brought down for a good landing, This was both a reflection of the model and pilot.

The model now pulls 700w at take off.

For the moment I am repairing another 10 year old model. It is my intention over the coming weeks to take some more data and finish the model decoration. Until then, there will be a break.

Nigel R09/10/2019 08:48:33
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Crikey Erfolg that did get hot!

Good to hear its sorted, time to enjoy the model now.

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