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Author Topic: Spin Up  (Read 1393 times)
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DennisK
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« on: June 20, 2008, 09:18:56 AM »

I recently got a "Spin up" plan from Mark Benns.
Has anyone here built one?
It'll be my first DLG, am looking forward to start building in a few weeks time, once the schoolyear's over. Roll Eyes

Dennis
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flyingfish
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« Reply #1 on: June 21, 2008, 11:03:53 PM »

HI Dennis,

Yes I've built a Spin Up - I've got a Spin Up 42 which I haven't launched discus style yet - but I have test glided it - and I'm fairly happy with it. I built a number of Sting Aero javelin style launch kits first.

For my first Spin Up 42 I went for the plywood reinforcement spa, which is built in to the wing (I don't know if the same arrangement is on the 36 plan). I'm happy with the model - but it's a bit heavy and if I could go back in time I'd probably order the carbon reinforcing straightaway and use that option. A heavy model is not what you want to get the best times - but as long as it's efficient in every other respect - it can be a good practise model and well.. from my brief experiences of competitions...it all comes down to picking lift so a model that's a few grams overweight may still do very well unless there is no lift available on the day... and then you want a light well trimmed model - well.... you want a well trimmed model at all times!

I'm now commencing a second model - in which will be built in a similar way to Peter Lloyd's TLG's which he posted on the Small Flying Arts site. Thankyou Peter. So it will be a 'built up Spin Up!' This means - balsa to the high point of the wing - then ribs capped with carbon, and balsa sheet -probably 1/16 to the TE, with the TE capped also with a trapezoidal carbon TE. Then the whole wing has to be covered - and nearly everyone seems to agree Polyspan is best. Airspan is bright and colourful but a bit of a pain to attach properly - I've used airspan for trim on the first model - over the top of the solid balsa wing.

Since it sounds like you are building from a kit, and if it is your first model - I'd stick with the all balsa wing - nothing wrong with that - and then it's just a matter of deciding whether to use the internal plywood, or the wizz bang super thin carbon spar top and bottom at the high point. My plywood reinforced model may have come out a bit heavy because of me using too much epoxy, rather than the plywood being an inherently poor choice. I'd be interested in what others think of the plywood option.

Cheers,
Keith
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DennisK
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« Reply #2 on: June 27, 2008, 05:52:16 AM »

Hi Keith,
Sorry about not replying earlier.
The 36" plan does indeed show the plywood reinforcement spar as well.
I'm building from the plan and will probably use the thin carbon spar reinforcement as the price difference to plywood is almost nil here.
Would love to see pics of your built up 'spin up' when you get it done as I have been thinking about this option as well.

Dennis
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Ployd
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« Reply #3 on: June 27, 2008, 09:41:43 AM »

Hi Dennis
Without seeing the plans I get the impression that the plywood is only used across the dihedral joint and not the whole wing Huh If that is the case then it will be following American practice at the moment. Personally I don't believe it needs it if you run a strip of fibre glass cloth across the joints.

Hi Keith
Don't worry too much about the finished weight of your model (mine are now up to 120 grams Shocked ) they work quite well. On your new wing try and sand down the 1/16" sheet to something like 40 thou (1mm) thick or conversely taper it from T/E to where it meets the leading edge sheeting and note; the bottom sheet goes from L/E to T/E, don't try to butt joint it the the L/E portion, has been done and that is where it failed Angry

Ployd in OZ
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flyingfish
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« Reply #4 on: June 28, 2008, 12:57:47 AM »

hi Dennis,

I'll look forward to learning how you go. I was hoping to do my first Discus launching this weekend but right now it's too windy. Yep - I'll put pics up when I can. I'm waiting for my Olympus to come back from the repair shop.

Peter - On the Spin Up plans - the plywood reinforcing runs the whole length of the wing.

Yes - I've been thinking about sanding the 1.5mm plank down and I wasn't looking forward to it. Tapering aft of the frontpiece seems the better option.

Keith.
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Ployd
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« Reply #5 on: June 28, 2008, 08:30:14 AM »

Hi Keith

Looks like the ply spar serves the same function as my vertical grain carbon capped spar does Wink adds strength to a floppy wing which Len found out and rectified with lots of carbon tow.

Ployd in OZ
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flyingfish
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« Reply #6 on: June 29, 2008, 08:14:37 AM »

Hi Peter and Dennis,

I neglected to mention on my first post that with my first 42 I used the spanwise plywood spar AND strips of glass cloth about 20mm wide over the dihedral joins - (10mm either side) AND then, little squares of carbon tow epoxied top and bottom of the stress points. That amounts to eleven of these little squares altogether - four on each dihedral break at the high point, one top and bottom at the throw peg, and one on top of the centre of the wing at the high point. It seemed like a lot but I did as the plan told me.

The model has come in at 160 grams - approximate wing loading of 14.5 grams per decimetre - that includes the elevator surface. An F1H built at exactly at 18 decimetres and weighing 220 grams is 12.2 grams per decimetre - so I feel like I'm going to have to do better! Like I said in my first post - this heavy beastie should be a good practise model anyway.

Keith
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flyingfish
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« Reply #7 on: June 29, 2008, 07:07:36 PM »

Hi Peter,

I'm curious... What would the wing loading of your TLG's be approx?

Keith
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Charos
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« Reply #8 on: June 29, 2008, 08:43:40 PM »

Flyingfish - from Peters website.

http://www.pelaero.com.au/


"MORRIS DANCER DLG ver. 2.1 - 35" span Competition Tip launched Glider

Available as a full-size plan, this model has the largest wing area (10.25 sq dm or 160 sq") of all the 36" span plans or kits on the market and comes with 2 styles of wing construction. Not a beginners model or suitable for r/c.

 35" projected span (89cm), length 32.5" (83cm), weight 110gms."
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flyingfish
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« Reply #9 on: June 29, 2008, 09:02:13 PM »

Thanks Charos,

I've been to that page before but for some reason the information didn't click in.

flyingfish
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BEAR
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« Reply #10 on: October 05, 2010, 02:00:37 PM »

There's a thread in the tip launch glider section on building Mark Benn's Spin up 42 with some input from Mark. I don't know how to put a link in I'm afraid Huh

http://www.hippocketaeronautics.com/hpa_forum/index.php/topic,3576.0.html
« Last Edit: October 05, 2010, 07:06:27 PM by Ratz » Logged

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deltabravo
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« Reply #11 on: October 06, 2010, 02:21:24 AM »

Hi Dennis,

take a look here:

 http://www.rc-network.de/forum/showthread.php?t=146490

Have fun with it! If you find some time, please report as well in the rc-network-forum!

regards

deltabravo
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