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Author Topic: Cassutt NoCal  (Read 8659 times)
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piecost
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« Reply #75 on: August 14, 2021, 09:06:43 PM »

John,

Yes, you are correct. I am very out of practice flying and thinking about flying. Thanks for spotting it. I am surprised that this is the case with a thicker motor.

I didn't mention that I launched the model and it turned the opposite direction to what I was expecting. It also brushed against my mates new F1D model. Luckily doing no damage, especially as he gave me a lift to the event.

I had a great time flying after a long break even though I broke 3 out of 5 models flown. At least I didn't loose any in the ceiling. The place has 18" wide electrical conduits which may still have a model or two of mine from a couple of years ago.

Tim
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OZPAF
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« Reply #76 on: August 15, 2021, 09:19:26 PM »

Well good luck with it Tim. Operating on the limits of structural strength, and flying speeds must be a great trimming challenge - the more rewarding when finally it falls into place and you understand why.

I flew EziBee many years ago - but not in an overly serious way and enjoyed the occasional long flights. I'm guilty of enjoying all the classes of flight from RC, CL to FF - outdoor to indoor.

John
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piecost
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« Reply #77 on: June 05, 2022, 01:42:28 PM »

I had a productive trimming session at OFMAC giving both models a shakedown. Airframe 2 flew well from the start but despite being careful hit the roof beams several times, luckily not hanging up. Often recovery of the model results in a nose dive breaking the motor stick. So, I put the model away after this flight.

My original model demonstrated the same trim problem experienced at the nationals at Lee Valley a few years ago, that prevented me from placing in the competition. The model ran out of nose up tailplane trim adjustment. It would not climb after launch. Careful inspection showed that the removable wing was not sitting properly on the fuselage. There was a nearly 2mm gap at the wing trailing edge. This caused the nose dive and increased down thrust. Fettling the wing seat cured the problem.

I did not get the model to climb over 10' height but was happy to fix the trim problem and put both models away intact ready for the nats in September.

I built these models so long ago and have used them so little that I can almost look at them dispationately. I noted that I had not labelled the parts so sometime had tried to use the wrong propeller in one nats competition. My early 12" propellers had too great a chord and didn't climb. Later ones had 20% less chord and worked well. But I cannot easily tell them apart.

I also notice the importance of locating the rear rubber peg behind the wing trailing edge to aid attaching and removal of the motors. I wind the motor on a stooge with a torque meter and it is vital that the motor can be attached and removed reliably. The propellers have a reverse S-hook which is a little fiddly, but on model I made the rear hook a reverse shape as well. This was nearly impossible to remove a partially unwound motor so I ended up unbending the hook on the model.

On model #2, when I moved the hook aft of the wing I replaced it with a simple conventional hook which worked.much better.







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piecost
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« Reply #78 on: June 05, 2022, 01:52:17 PM »

The second picture, on its side, shows a K&P 10:1 winder with a digital counter, also from K&P. This works well. I made a plywood attachment to fit into the existing winder mount shoe which incorporated a brake. The wire torque meter is calibrated up to 90 g.cm. under the 20' beams I wound to a moderately low torque of 50 g.cm and backed off to 35 g.cm for launching.  Neoprene o rings on the motor aided installation on the model and removal and reattachment to the stooge to measure landing torque and turns.


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Mefot
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« Reply #79 on: June 05, 2022, 02:11:07 PM »

Good to hear these are still performing after so long. I notice Don Slusarczyk has built a 4.3 gram version. Do you think you'll eventually produce a lighter one ?
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piecost
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« Reply #80 on: June 05, 2022, 02:42:48 PM »

I don't see how to get it that light without sanding the tissue thinner! There are nearly two grams of tissue on the model.  Condenser tissue is not allowed. The aft fuselage and tail are rather light and delicate and I don't see obvious areas for large weight savings. But, I could remove a fair amount of wood from the nose and taper the wing leading and trailing edge spars. A lighter undercarriage could be used at the risk of increased risk of breakages . The tube and boom feel about the right stiffness/mass so not much room for savings there.

The UK indoor duration rules have reduced the minimum airframe weight so a Cassutt is not nessesarily the optimum model anymore. But, I think that my plane is still competative.

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Indoorflyer
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« Reply #81 on: June 05, 2022, 03:55:16 PM »

Some Gampi tissue is about the same weight as Condenser paper.
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piecost
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« Reply #82 on: June 05, 2022, 04:27:49 PM »

I bought a selection of tissues from a specialist art supplier and the really light stuff was more like a porous mesh. I suppose if I was really keen I could try the lighter stuff and see how well it flies.

I use Gampi of about 15% less weight than Esaki on my Legal Eagles.
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dslusarc
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« Reply #83 on: June 06, 2022, 05:17:43 PM »

The light Cassutt took some work to get it down to 4.3 grams but is doable. Not all Gampi is the same, you need "conservation" gampi which is 9gr/sq meter. It is also pricy. About 5 times the cost of Esaki.
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piecost
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« Reply #84 on: June 07, 2022, 03:32:19 PM »

Thanks for your continued long term advice on this thread Don!
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piecost
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« Reply #85 on: June 07, 2022, 05:25:01 PM »

Some samples of Japanese tissues I obtained. I don't think they are the same as Gampi. The samples below 5g/m2 are more like a fine mesh, those above are less porous. The 7.3g Tengucho is made from Mulberry looks like heavier Gampi.

Skymon reminded me about lens tissue and I am searching my workshop for a sample that I bought then forgot about.
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piecost
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« Reply #86 on: June 07, 2022, 05:35:23 PM »

Found the Lens tissue. It is 9 g/m2 at looks slightly more porous than the 13 g/m2 Gampi use to cover a Legal Eagle tailplane, shown in the photo.

No idea about is resilience or shrinkage but it has potential
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piecost
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« Reply #87 on: June 08, 2022, 01:02:18 PM »

Switching from Esakii to Lens tissue would save around .66g taking my model from 6.17g to 5.51g.
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dslusarc
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« Reply #88 on: July 11, 2022, 09:51:43 PM »

Flew my light version of the Cassutt at the Johnson City contest last weekend and had two 8:00 official flights in FAC Nocal and won first place. I was getting up about 80 feet and pretty much dead sticking. Needs a longer loop. I think I get get 10 minutes there if I push it a little. That will be for next year.

The little box I am holding in this photo is a box my mom made for me that I keep my stop watches in. She put on the top of the box a copy of a photo of my dad from Johnson City in 1994 when he won 6.2 gram Nocal with his Cassutt racer. So here I am holding my Cassutt racer after winning in 2022 (28 years later) in Johnson City :-)  

Don  
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Mefot
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« Reply #89 on: July 12, 2022, 06:13:51 AM »

Is that a one piece model now Don ?
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dslusarc
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« Reply #90 on: July 12, 2022, 09:13:29 AM »

Yes one piece model.
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piecost
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« Reply #91 on: July 12, 2022, 06:49:19 PM »

Thanks for sharing your success Don. A really impressive performance. I love the family connection as well

Tim
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Skymon
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« Reply #92 on: July 26, 2022, 08:52:20 AM »

Thanks for sharing your success Don. A really impressive performance. I love the family connection as well

Tim
I want to see ten minutes out of your model now Tim Smiley
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piecost
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« Reply #93 on: July 26, 2022, 10:54:00 AM »

Easy; over 10 flights
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