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Sep 13, 2010, 12:55 PM
SB-28 UK Display Pilot
GeeW's Avatar
Roger L
Any progress as I want to know whether my visa cards going to take a bit of a hit this month or not?!
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Sep 13, 2010, 03:04 PM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Pretty much done - I'll post an update tomorrow although the wind doesn't look good for a maiden flight this week.
Sep 14, 2010, 03:40 AM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
The ASK is now complete and ready for its first outing. This is the fourth FlyFly ďscaleĒ sailplane in my fleet and in my opinion represents a continuing improvement on the part of this Chinese manufacturer. There were still some inconsistencies and quibbles and while one could say that for the price of well under $200 delivered EMS to the UK such inconsistencies are to be expected I donít accept that. Nothing that was wrong would have cost significantly more to have been right and Iíll be putting in a report to hobby88.

Comments on the design in general:

I canít measure the fuselage wall thickness but Iíd say it was up on earlier models - good

As previously mentioned a big fat 10mm carbon joiner - good

New wing retention method Ė not sure ... easier to fit but Iím worried it could cause fuselage damage

Piano wire pull-pulls I threw away Ė too heavy. I used 20lb dacron fly line backing which is hard wearing, zero stretch, even lighter than wire cable and easier to manage. And it's a snazzy shade of orange too

Full set of hardware but the control surface horns are cheap and I used my own.

Ditto preformed pushrods which were thick enough to be serviceable on an Airbus 380

As previously mentioned the hinging of the ailerons and flaps limits their movement. At the moment Iím leaving these as is until Iíve checked out any limitations in flight performance.

Nose, belly and tailwheels are all unsprung except for foam tyres on nose and belly. I have severe reservations about the compatibility of my landing technique with that nose wheel. I changed the supplied unit for a lighter weight one with a bigger and somewhat softer tyre. This wheel will break before the wheel mounting does.

Although I commented in a previous post that the cockpit floor was moulded to simulate the upper part of the real thing it became apparent that it wasnít at all. It would need pilots of about 1/10scale or smaller to fit. I did some chopping around to fit the head and upper shoulders of a 1/6 bust. Iím not bothering with a second pilot Ė my enthusiasm for carrying token gestures around the sky has its limits.

The instructions say use a rubber band inside at the rear and a self tapper at the front to retain the canopy. I donít like that so Iíve used my own Not Very Good arrangement. Canopy fit and retention is a development opportunity for FLyFly.

I lost the plot on what ballast Iíd put in but itís balancing at the stated 65mm with about 300g of lead up front (about 10 oz in US money) and a four cell 2100 NimH square pack. I could probably have got a bigger battery in but what Iíve used which is one of the second generation energy retaining packs will be fine for my purposes.

There is actually a lot of free room under the canopy apart from the steering servo and you could probably do a proper interior at least for the front pilot.

I think Iím right in saying that the only thing your $10 extra for the air cadetís version buys you is a vinyl decal sheet. I prefer waterslide to self adhesive vinyl but I draw other builderís attention to the fact that the ďAir CadetsĒ decal is sided. I didnít notice this and following the well proven law of physics that any slice of toast falling freely under gravity will land marmalade (jelly) side down I put the first one on the wrong side. I donít think that one person in ten would notice but I compounded my minor stupidity with an Act Of Great Stupidity by trying to remove it again. Came off ok but promptly twisted itself up becoming an instant write off. So I was left with the chore of scanning the remaining one into the PC, photoshopping a reversed version of it and then printing waterslide decals.

For those who donít feel the need to follow me: one end of the decal has a little white arrow THIS GOES AT THE FRONT!

So overall pre-flight conclusions?

Better than the others Iíve built (and most certainly including the one and only European made (S2G) sailplane Iíve experienced.)

Some silly details which would cost between zippo and $10 factory cost to put right. It may not be a LET or a Multiplex or whatever but I find it really hard to see where the difference in cost comes from. Getting an airfoil right costs nothing, I canít see the difference between a FlyFly fuselage moulding and the best you could get as justifying more than $100 tops. I donít know about differential costs of wing manufacture.

This is not to bad mouth the expensive European stuff Ė let those who feel happiest with those continue to buy and fly them Ė I may do myself one day Ė but for the moment this baby hits my spot.

Photos and flying weight check to follow - raining too hard for photos right now
Sep 14, 2010, 04:32 PM
SB-28 UK Display Pilot
GeeW's Avatar
Thanks for that. I look forwards to seeing the piccys.
I hope to be able to resist til at least then (maybe)
Sep 15, 2010, 03:54 AM
Registered User
Difference between costs comes mainly from material and labour costs.
Europeans ones are epoxy and will last for years of flying. Most chinese manufacturers uses polyester instead. Less stable and more prone to warpages. Wood wings are easy and cheap, hollow mold wings are more labor intensive and requires more knowledge, but gives a more accurate wing section.
Sep 15, 2010, 04:23 AM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Here's the picture gallery. As an aside, and really nothing to do with the ASK, I've included a "Study in chords". The size of the wing on the Habicht I just acquired really brought this home to me. Of course you have to allow for scale effect. Although all four wings in the picture are off 2.6m span models (Minimoa is 2.4m) the DG1000 is smaller than 1/7 scale, the ASK and 'Moa are the same at a little smaller than 1/6 scale and the Habicht is 1/5" scale.

The weight of the ASK tots up (with flight battery installed) as:

Fuselage 1241g (DG1000 800g)
Wings 415g (DG 181g)
405g (DG 199g)
Joiner 54g (DG 60g)

Total 2115g (DG 1249g)

So, like its owner, it's on the chunky side! Interesting the DG1000 wing I just had to rebuild after ripping the joiner tube loose, and which repairs you'd have to characterise as "robust" still weighs 18g less than the other. God knows what the difference was before!

If FlyFly figures are to be believed the ASK has a wing area of 30dm2 so wing loading of 70g/dm2, and the DG 28.5dm2 so 43g/dm2.

Do those two wings in the study in chords look like 30 dm2 plays 28.5 dm2?
Last edited by Roger Lombard; Sep 15, 2010 at 04:31 AM.
Sep 15, 2010, 04:42 AM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Originally Posted by wilerbee
Difference between costs comes mainly from material and labour costs.
Europeans ones are epoxy and will last for years of flying. Most chinese manufacturers uses polyester instead. Less stable and more prone to warpages. Wood wings are easy and cheap, hollow mold wings are more labor intensive and requires more knowledge, but gives a more accurate wing section.
MY polyster ones would last for years of flying. It's not my flying that busts 'em up! It's my landing

Appreciate what you say though and the labour cost component is an advantage that will diminish as social expectations in China continue to increase. But I'd like to know what the material cost variance between polyester and epoxy is. Typically you can get a new spare polyster fuselage for under $100. For myself I'd like to see the Chinese following the European manufacturing methods but by giving them some competition make sure that value in the European kits is optimised. I'm not sure it is at the moment?
Sep 15, 2010, 06:01 AM
Deniable plausibility
Shedofdread's Avatar
Polyester is typically, about a quarter the cost of epoxy (this can vary depending on amounts bought, suppliers etc) but the real cost advantage of polyester is mould cycle time. Put simply, in a given period of time you can make more parts.
Sep 15, 2010, 07:36 AM
Registered User
Damian Couzoff's Avatar
Looks great roger,your photos are clear and interesting.I have quite a few from flyfly as well-ASW 28,CONDOR,DG808S.Keep up the good work,look forward to your flight report.regards damo
Sep 15, 2010, 01:48 PM
Registered User
Hi Guys:

HobbyClub will be receiving the ASK-21 and Fox within the next 10 days.
Flaps on the ASK-21 are very interesting for small landing areas.

Already carrying the DG-1000, Condor, Salto, DG-808S, ASW-28

best regards,

Sep 18, 2010, 07:57 AM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Now ain't that just dandy? Wind today looked good for a maiden flight so this morning I assembled the bird for a final home check over. Even to the extent of, for the first time, bothering to fit the screw-in wing retainers though we certainly weren't going flying. Or I should say attempting to fit the wing retainers. Couldn't pick up the thread in the wing and upon checking it wasn't hard to find why. There's a 9mm - 3/8" - discrepancy between the hole in the fuselage and the threaded bush in the wing root rib. On both sides. Pictures show the story. So.... redrill the fuselage to align with the bushes in the wing or fit new bushes in the wing? No brainer, make drill template and redrill fuselage .......except.....if you look at the 8th picture in my sequence in post #36 you'll see that the "wrongly positioned" hole is just in front of a bulkhead. Guess how far in front, bearing in mind the new hole needs to be 9mm rearward and slightly higher ....correct, you win today's special prize - about 7mm in front so a new hole in the correct place would pretty much go straight through the bulkhead.

So, it's thinking cap on and consider how to fit new retainer to wing root rib to line up with the existing hole.....

Chinese sailplanes lol!
Last edited by Roger Lombard; Sep 18, 2010 at 08:16 AM.
Sep 18, 2010, 04:08 PM
Registered User
I have some nice white tape if you need any Rog....

Sep 19, 2010, 07:36 PM
It's not going to build itself
TRISME's Avatar
Looks like a nice lifty airfoil.
Sep 19, 2010, 11:38 PM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Sent the pictures with a report to Hobby88 over the week-end and to be fair I've had a pretty much immediate apologetic response from FlyFly. Seems I got one of the first off production samples. They realised on that preproduction run that there was a problem because the wing retainer location coincided with the internal bulkhead, as I'd already discovered for myself, above. So if I've understood them correctly I've got a production fuselage with a pre-production wing.

Having thought about the problem at the week-end I'd already decided that simply drilling another hole in the correct place on the wing root rib, to align with the existing hole in the fuselage and then glueing in a nut wasn't going to be a secure enough anchorage. The nut had to be on the inside of the root rib, not in it.

So, scalpel equipped with new blade, we carried out surgery. Sure enough inside the double layered ply wing root ribs is another double layered ply block, profiled to the root rib, with a captive nut in it. Whilst the screw hook wing retainers on the ASW28 and Salto might pull out fairly easily you could hang a bus on this. Which would be good if I hadn't got to get it out, because yet again Murphy's law applies and the block ends just where I need it to be re-centred So after a struggle I managed to get the captive nut and its block out. Now got to reshape it and move it forwards. To be continued....
Sep 20, 2010, 05:01 AM
Confused? Who, me?
Roger Lombard's Avatar
Thread OP
Well, both captive nuts are out of the wings but it can't be done without damage and I'm becoming disappointed about that.

Now I've got to reprofile the captive nut mounts to allow them to be re-installed 9mm further forward and after that we'll be into trying to repair the wings with the minimum of cosmetic damage but just the amount of handling and pushing, shoving, cutting etc has taken its toll - lot of hangar rash starting to show

EDIT - I haven't made it clear, and I should have, that I'm going in from the underside.

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