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Jul 30, 2019, 03:39 AM
Youtube channel : solentlifeuk
solentlife's Avatar
MPF is available in Europe ... it was just a couple years ago that I think it was Flite Test who set this up ... but to be honest - with Depron still available (Europe mainland at least) - its not really caught on.

As to 'dents' and 'thumb marks' - White Model Depron has that as well ... and the Depron grade that's available now since the stop of Model Grade production - has that ... in fact I see no difference in the White Depron today from the Model Grade before.
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Jul 30, 2019, 08:58 AM
treefinder
springer's Avatar
I used to be able to ship a 17 sheet full size box of MPF to the EU for around $50usd, but no longer, $65-75 for a $40 box. . . Shipping was no doubt the primary cause for it not catching on overseas. Why pay a lot for an unknown when you can easily get the original Depron? Incidentally flitetest was never involved in any aspect of Model Plane Foam development or implementation, other than they did a video spot on us at a HH Indoorfest many years ago. The lack of paper on MPF prevents its use with their build techniques - not that one can't use it, but one needs paper for the cut paper/pick out foam/fold method.
The XPS vs EPP situation is interesting. My read is it depends on the type plane one is interested in building. Personally, I like the sandability of MPF/XPS vs EPP and the final appearance it can produce. There is ample (though anecdotal) evidence that MPF is more crash resistant than Depron was. A 3D kit maker in Sudbury, Ont. (Who unfortunately is no longer with us) became a big customer because he found that his machined truss profile planes in Depron broke on first crash, while the same designs in MPF merely bounced. Bob, is, of course, pretty vocal about it's durability as well.

Regardless, we all have our preferred build subjects, materials and methods, and will use what is available to us.
Jul 30, 2019, 09:27 AM
Youtube channel : solentlifeuk
solentlife's Avatar
Quote:
Incidentally flitetest was never involved in any aspect of Model Plane Foam development or implementation,
All I remember a few years back was watching a video and they announced that the Foam sheet they use for their models was made available in Europe ... I am quite likely wrong in which actual foam it is ...
I remember checking out the website they quoted .... but the sheet size was too small for my builds. I can buy 1250 x 800mm sheets of Depron (20 sheets a box) for about 80 euros. incl delivery ....
Jul 30, 2019, 02:48 PM
treefinder
springer's Avatar
If it was smaller than Depron sheets it was flitetest's version of Readiboard also called DTF (Dollar Tree Foam) 20"x30" sheets.
Aug 10, 2019, 10:14 PM
Registered User
ggrimley's Avatar

Field Dart Polaris XL


Might need another kit!!!! It was the wind... NO... it was a system failure... NO... The fog - Well there was fog,.. But just a plain dumb move... First flight out after "Sea Darting, I tried chasing grubs in a hay field, but alas, they were too deep in the ground...
Aug 10, 2019, 10:42 PM
Registered User
Quote:
Originally Posted by ggrimley
Might need another kit!!!! It was the wind... NO... it was a system failure... NO... The fog - Well there was fog,.. But just a plain dumb move... First flight out after "Sea Darting, I tried chasing grubs in a hay field, but alas, they were too deep in the ground...
Woops! Been there... Kinda. Ailerons were reversed. Once on maiden... Rolled pulled up, almost saved it. Hit the water and blew the battery right out of the nose! Pics are on here back quite a ways!

We should have some kits by the end of the month.
Aug 11, 2019, 06:21 AM
Look out for the mothership
Mrwaz's Avatar

Polaris with no elevator control


A mate flying his Polaris last week end without elevator control. He had previously rigged it with elevons to get extra manoeuvrability and arrived at the lake to fly only to find that he did not have elevator control (since found to be due to a TX programming error). Rather than not fly he thought he would give it a go anyway.....

Polaris flight with no elevator control (2 min 26 sec)


What a remarkable plane!
Aug 11, 2019, 07:29 AM
Registered User
That was why when flaps were attempted on the Polaris, they didn't work--they acted as down elevator. Also the basis for the Arrow version...Pete M
Aug 11, 2019, 08:41 AM
65 years of RC flying
Daedalus66's Avatar
Thanks for sharing that interesting video. Makes you think it might be worth trying a stabilizerless version (like Laddieís Arrow).

I experimented with flap action on a Polaris XL. I tried three configurations: Flaperons (lowering ailerons), Spoilerons (raising ailerons), and coupled flaps and elevator (ailerons working in conjunction with elevator).

Flaps down required a lot of up elevator to compensate. Quite disconcerting if you forgot that!

Spoilerons up about 20į produced a very stable steep descent and could even be used for hands-off landing. But donít try it with throttle on or you get a very quick loop!

Coupled flap/elevator gave stronger pitch control.

Interesting, but I didnít find any of them suitable for long term use.
Aug 11, 2019, 08:56 AM
Youtube channel : solentlifeuk
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Given the size comparison of the combined ailerons vs the elevator ... and how far back the ailerons are ... trying to use them as Flaps or Spoilers must be questionable.

IMHO
Aug 11, 2019, 01:03 PM
65 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by solentlife
Given the size comparison of the combined ailerons vs the elevator ... and how far back the ailerons are ... trying to use them as Flaps or Spoilers must be questionable.

IMHO

Thatís why I didnít pursue the experiment. It was, however, fun at the field and lake to line up in what looked like a far too high approach, throttle right back, flip on the spoilers (up aileron), then take fingers off sticks and let the model descend in a level attitude at slow speed and steep angle until it quite gently hit the grass or water. If I did want to steer, the setup was fully controllable with rudder and aileron, and the glide could be stretched with a small amount of throttle.

I disabled the setup the day I unthinkingly switched on spoilers with about half throttle. The model, of course, went vertical and would have looped had I not chopped the power. In the ensuing confusion, it ended up about 15m up a tree. I spent the next couple of hours retrieving it with a long thin pole.

I recall someone on this forum who swore by full-time coupled elevon and elevator as the way to set up a Polaris.
Aug 11, 2019, 05:30 PM
Park Jet Guru
jetset44's Avatar
Thread OP
Quote:
Originally Posted by Mrwaz
A mate flying his Polaris last week end without elevator control. He had previously rigged it with elevons to get extra manoeuvrability and arrived at the lake to fly only to find that he did not have elevator control (since found to be due to a TX programming error). Rather than not fly he thought he would give it a go anyway.....

https://youtu.be/4OMHVxl_G2Y

What a remarkable plane!
Fascinating! I'm not surprised it was flyable, but am surprised at how WELL it flew without elevator. Thanks for sharing!

Steve
Today, 10:25 AM
Mk9
Mk9
Registered User
Mk9's Avatar
Quote:
Originally Posted by Daedalus66
Thanks for sharing that interesting video. Makes you think it might be worth trying a stabilizerless version (like Laddie’s Arrow).

I experimented with flap action on a Polaris XL. I tried three configurations: Flaperons (lowering ailerons), Spoilerons (raising ailerons), and coupled flaps and elevator (ailerons working in conjunction with elevator).

Flaps down required a lot of up elevator to compensate. Quite disconcerting if you forgot that!

Spoilerons up about 20į produced a very stable steep descent and could even be used for hands-off landing. But don’t try it with throttle on or you get a very quick loop!

Coupled flap/elevator gave stronger pitch control.

Interesting, but I didn’t find any of them suitable for long term use.
Thanks for posting that Waz - it was me that was desperate enough to risk my plane. As my flying has improved (not hard), I enjoy coupled ele + flaperons more and more, and I often now forget I've got them coupled, the flare you can get is brilliant - but getting it wrong and ending up slow, nose up with full power on in an attempted go around with massively sensitive pitch can be a little hairy for my old reflexes and ropey skills. Given it will do a full power loop in not much more than the fuselage length in coupled mode, I guess that's not surprising.

I like the idea of flaperons- presumably I could play with mixes to try and get that to work as an air brake ...

Do you mean surgical removal of the horizontal stab? Would be an easy mod, not so easy to reverse
Last edited by Mk9; Today at 10:28 AM. Reason: not spoilerons, flaperons - though I guess both could work...


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