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1st 2020 2m Hi Start 14 day Duration Challenge


martynk
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Hi John, 

 

I think the best people are getting is about 180 feet, most of the energy is lost in the climb. I don't think that I have got much more than 160 feet, possibly because  my launch technique isn't ideal.

 

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I had an altimeter in my 1.5m Skidoo and averaged about 80-85m on a good launch. I haven't measured with the Slite but it's probably a bit less sure to extra weight.

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StraightEdge

I checked my height on one of my better launches with the X-RES and I'm sure it was around 80m from memory.

If there's 10m of bungee and 50m of line, that surely means there was still a fair amount of stretch (20m, or 3x relaxed state) in the bungee?!

So how much of the height is due to 'kiting' into the wind, and does launching into a strong thermal effect the launch height?

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  • 2 weeks later...
StraightEdge

Well done Jon! 👍

I'd better get a shifty then - picked up a used PuRES last week which needs recovering and stiff pushrods changing to pull-strings etc - but at least I can do this while it rains for the next five days!

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I picked up Ian M's other old X-RES at the weekend.  Whilst in better shape than Jon's version, it still needed a few warps removing.  Made me chuckle that even the box was warped :)

bit rushed but got all in a flyable state last night and this morning.   Weather was quite a bit windier than forecast but good lift.

i spent quite a bit of time hand launching and checking trim and CG.   I've not used a bungee launch since I was 12 years old.  By the time I got my act together the wind had picked up and it had gone cool.

Performance is quite good, managed a few 6 min flights.  On a decent day I think some good times could be had.

it pulls to the left on the launch so need to revisit the wing again.

All in all an enjoyable experience.  Only switched back to DLG when wind got too strong.   Like going from a station wagon to a Ferrari :)

 

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StraightEdge
56 minutes ago, cirrusRC said:

I picked up Ian M's other old X-RES at the weekend.  Whilst in better shape than Jon's version, it still needed a few warps removing.  Made me chuckle that even the box was warped :)

....

Like going from a station wagon to a Ferrari :)

 

Good analogy!  But a pleasure to be had in both 'vehicles' of course.

My new second-hand PuRES still has warps even though its wing has got substantially more carbon it than the X-RES - maybe just a result of delicate wing structures being pulled out of true by the film over time?

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Well done Jon

I'll update the tables a

nd start a new post later. 

Has one of those days today :(

 

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yes Jon - I found it addictive.     Plenty of walking but kinder on the back.

these models are at the limit of lightness given the materials in use.   They just seem to be too delicate for warps not to be an occupational hazard.     Part of the maintenance and up keep i suspect.

Is your PurRES the one from Leo?

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StraightEdge

David, yes the PuRES it was Leo's.  All transparent green with a clear-finished balsa fuselage, very attractive but aside from the 'storage warps' I've already learnt the lesson of adding bright contrasting colours and tones for better distance vision, so I'm re-covering from scratch.  Also the V-tail pushrod wires were very stiff in their tubes, so I'm springing the control surfaces and using kevlar string.

Its a different pace, but with the X-RES I was already finding it less hectic and able to concentrate more easily on reading the air and 'guiding' the model.  Once one's got a sense of thermal activity on the field, their rhythm and general direction etc, then launching for longer flights becomes very pleasurable.  Over longer grass or rougher ground  a parachute would be better than the simple pennant:  one can then see where its coming down more slowly, usually landing closer back to the launch position...  i.e. I've already gained much experience of converting my legs into a weaving loom for transparent fishing line !!

The only downside of these 2mRES models is their fixed camber, limiting use to relatively calm days.  So Leo was also selling a full-house FXj 2.54m (100" in old money) which I picked up as well.  Its 100-150g too heavy, mainly because he covered in Oratex (presumably for robustness on the slope etc), so that's also going to get a make-over with Oralight, aiming to get it down from 940 to at least 800g or so.  According to designer Robert Scheibelhofer of rs-aero it will launch well enough on the same 10m of 6mm bungee as the 2mRES, so will probably become my 'mount' for our usual briskier wind conditions!

 

DSC_0234.JPG

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Well done Jon

 

Great start to a late start season.

Table post created and 2nd Challenge post created.

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Jon.    +1 on the parachute.   First thing I'm going to change.   

Hadn't realised the weight saving of oralight was that substantial.     Think the XRES is covered in standard oracover according to the packaging in the box.    Not sure though.      I'd been warned that oralight tends to look tatty very quickly.    Perhaps that's more down to the skill of the person ironing it on.

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StraightEdge

Don't know about tattiness, but Oralight transparent is 36g/m2 whereas the Oratex is 100g/m2.

On the FXj this will save 55g on the wings,  about 10g on the tails and therefore roughly 20g less nose-weight, total saving estimated 85g.

The fuse was finished in yacht varnish, might not have been sealed first (?), so easy enough to cut back to bare wood and re-finish/cover.

The ailerons have KST08 servos, the flaps Bluebird non-HV and the fuse is empty.  I've got four spare KST's (two lugless and two with lugs from my old GO Mini), so that'll be KST's all round, whole system suitable for a 2s 450mAh LiPo.

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  • 1 month later...
Pete in Northiam

Ok, here we go.  My first day out with my RES-Eagle (RBC Kits from the March 2018 RCM&E plan) on Pevensey Levels in East Sussex and it's maiden flights off a bungee (postal standard 10m+50m).  Most of my time was sorting trim and learning what a crap batch of bungee tube I had bought as it broke three times before I gave up! 

My best time was a measly 3m10.3s - but it's a time on the board 🙂

I have taken delivery of another 50m of tubing from Amazon (Tansoole Latex Rubber Tubing ONE Continuous Piece,4×6mm, Pack of 50m) that's at least a different colour to the first batch.  Fingers crossed it's a but more durable.  Where do you other folk get yours?

Back in the air again soon.  

Cheers  --Pete Newman
BMFA 197508
BARCS 3869

 

 

Edited by Pete in Northiam
Wrong thread - reposted in the 3rd 2020 challenge thread
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