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TOPIC: Flying at Salisbury Plain

Flying at Salisbury Plain 3 months 4 days ago #622

  • ahmetcalfe
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At last I managed to get some flying in on Easter Monday at Salisbury Plain, it was a bit cold and windy in the morning but there was little turbulence so the models flew OK.
The wind dropped somewhat in the afternoon so it became a bit more pleasant to be there and it is a truly lovely place to fly.

I only flew two of my models the new Phantom F4 and a completely refurbished MiG 15 that I built in the late 1990's.

The F4 suffered from insufficient down thrust and tried to loop all the time but the very straight (and good) glide looked promising. After gradually increasing the area of a temporary down thrust tab inserted into the underside behind the exhaust protector plate, it few very nicely in a wide open circuit looking every bit a Phantom on full 'welly' streaking across the sky. I was pleasantly surprised by how stable it was -- except when the CG was too forward and after a stall it nosed dived to the ground! No damage despite the rock hard ground. Depron models rule!!!

In contrast, the MiG 15 had too much down thrust set on the motor and despite a floaty glide it only wanted to dive into deck when the motor was lit. I fixed this by re-positioning the motor with much less of a down thrust angle on it as the down thrust ramp I had built into the shortened exhaust trough was obviously too large.

Once modded in the field it flew in rather swoopy tight circuits- nearly hitting the ground at one point of the circle, then climbing up high on another. So it still needs another flying session to trim this out but it looks promising.

The tight circuit is caused by small warps in the wings which on the original model nicely counteracted each other, but I was foolish enough to try and eliminate them during the rebuild. :dry: I could only stop the turn with a little weight on one of the tips but I rather overdid it .
But, all in all, I am very happy with the MiG, and though the colour scheme is not completely authentic I think it looks the biz [Roger comment: I so do I! B) ]

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Last Edit: 3 months 2 days ago by rogersimmonds.
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Flying at Salisbury Plain 3 months 2 days ago #623

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Hi Howard,
many thanks for this nice report, looks like you had a good time trimming out your MiG 15 and Phantom in not too unfavourable conditions. Glad to see the MiG 15 is back in the air, and the Phantom looks to be an outstanding model. :ohmy:
I look forward to seeing them both do their stuff at Old Warden, which isn't too far away.

Anyone got the long term weather forecast? :whistle:
Last Edit: 3 months 2 days ago by rogersimmonds.
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Flying at Salisbury Plain 2 weeks 1 day ago #637

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Yesterday I went to Salisbury Plain again and did some flying with Rapier models but was frustrated by poor flights caused (in my opinion) by the high temperatures there, I‘ll try and explain.

The only way I could get a reasonable performance out of the motors when flying on a snow covered field in the middle of winter was to warm them up by keeping them next to my skin in my trouser pocket. So yes in my experience the cold definitely has a detriment effect by reducing the thrust available so I should not have been surprised by the much higher thrust levels I was now getting yesterday in the 27C heat. I did note an oddity though in that one very old green L2LT was not powerful enough to fly the Skyray so was apparently unaffected by the heat?

The Valiant and Comet for instance performed high speed loops which on the Comet caused the fuselage to part with its nose and tail when it hit the ground at the bottom of the third loop, ooops. In the case of the Comet it was an L2LT! and an L2X in the case of the Valiant. I eventually worked out what was going on and selected lower power motors and got some good flights with L2LT’s in my profile Skyray and with old green L1’s in my 1.6 x Bill Dean Spook which climbed to a considerable height in a series of steps. To fit an L1 into the L2 mount I had a sleeve which I had previously cut from an alu. drinks for just such an occassion and can be seen in the pic below. I used the same old green L1 in the Depron BAe Hawk designed for an L1 demonstrating once again that the power was well up to around at least 80-90mN's with a long high flight. Was it only me or has anyone else experienced this phenomenon? It can’t be just the batch of motors from the last year or so as the L1’s were from way back with crocked nozzles.

My Phantom F4 was out of action as I had left the aluminium foil heat shield and down thrust tab at home and I didn’t feel I could chance the Mig 15 with the unreliable thrust levels and the grass being too short to cushion any mishap.

For a bit of fun at the end of the day when the wind got up to about 7mph (and higher in the gusts) a friend lent me a small catapult glider to try with a Rapier. This had lots of dihedral and was quite heavily built so I cyano’d a carboard tube mount supplied with old LI’s on the top of the wing with a stub pylon and used an old green Rapier L1 again as I had done in the Spook. As the wing was skewed to the slightly to the left for the catapult launch I set the Rapier to give a little right thrust and balanced the rudder which also had been offset to the left with a bit of opposite wing weight. On the first flight the pylon was evidently a bit too high and caused a nose over as the motor reached full power but resetting the Rapier tube mount directly to the wing with a wedge to get the thrust line level proved perfect and the model attained better heights than it did with the catapult and much better than I have achieved before with any L1’s in the Jetex Wren for instance, resulting in some very satisfying long walks to find it.

Food for thought.

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The models that survived the day in one piece

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Spook showing the L1 and sleeve adapter for the L2 mount
Last Edit: 2 weeks 1 day ago by ahmetcalfe. Reason: Missing text
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