Hammer F3F

[DAVE MATTHEWS 2]

Thanks for the reply Phil, didn't know the wings were layed up with tow. I was thinking single blade underneath starting off laying along side the wing joiner box then out about 800mm, bonded in with epoxy. Is yours ballasted?, if so, how much? Cheers, Dave

[DAVE MATTHEWS 2]

Phil, just done the torch thing, and it looks like the tow extends 450mm along the line of the joining box (looks like top and bottom). might just leave it, especially if no-ones folded the wing yet!

[Phil Elliott 1]

Hi Dave. I apologise for leading you astray mate. I was working from memory last night

I got the wing out today and had a closer look. I need to do a quick repair so it wasn't such a big task!

I have taken photos and they show a lot of repairs - I have done several hundred hours on this plane and it is still as stiff as it was when I bought it. The photo's show just how durable the wing is. The poplar skin underneath was hit by a Wedge-Tailed Eagle, in case you were wondering. The chunk that I repaired on the leading edge (with 2pac polyurethane foam and carbon fibre) was where Hammer bumped into my car when I was trying to land!!!

Back on the topic now. The torch thing has revealed the joiner box, it extends 450mm into the wing and (from memory again) consists of two shear webs of 1mm ply with some poplar cap strips top and bottom.

There are some tows on the top of the wing as shown in the photo with the diagonal black tape, but it is difficult for me to detect the same tows underneath - your guess is as good as mine.

Mine also has a lightweight woven cloth under the poplar, but I am unsure if it is covering the whole blank.

I have seen the blejzyk hammer flying no ballast in 80km/h wind it will still move forward and is very controllable with low rates. However I would not say it is 'fun' to fly un-ballasted in these gale conditions. For what my opinion is worth, I will say that I would be more than happy to put 250g in a tube under the wing and give it a good caning. I reckon the wings would handle the added stress without too much bending. But once again, it is just my opinion.

In addition to my 'opinion' I have seen blokes add 600g to the model and fly it insanely fast, but with weight comes momentum and any mistake can become a disaster in the blink of an eye. A survivable 'rough landing' will become total disaster with disintergration when the fuz is carrying all that weight & momentum.

This forum wont let me post the pictures I edited for you - Sorry. Phil

I have posted the pictures here in post #8

[DAVE MATTHEWS 2]

Thanks for that Phil, epoxied in the joiner last night, which worked out great. Going to varnish my wings, the veneer's too good to cover! Might have a word with Arthur, but I'm quite happy with the strength now.

Cheers, Dave

[Phil Elliott 1]

That's great Dave, I like that you like that black poplar veneer. I have had some beautiful wood on some of my blejzyks. The Serafin had a bit of birds eye and a few tiny knots it the grain.

My eyesight isn't too good so I tend to go for brightly coloured covering film these days, but like you I always bite the bullet and go for water based varnish. You can add food colouring or fabric dye to give a transluscent colour as well. I added red ochre to the varnish for my hammer.

The hammer is worth building carefully and balancing well. If something is in doubt do it again because when you get to the field or the slope, you only have to point it into the wind and it will take off out of your hand with a gentle toss. Hammer is a misleading name for the model when the wind is light because it will fly at jogging speed all day. Winds as light as 20km/h are fine once you get used to it. You probably have more experience than me so forgive me if I am selling ice to the eskimo. I would wait for a day 25-30km/h to maiden the model and I reckon 30-40km/h is where it comes into it's element when weighing 1.3kg

I will put a ballast tube into mine in the near future too - probably just a 350mm length of 13mm aluminium tubing I reckon. That way I can just use a bit of cheap rolled iron bar for my slugs. That will give me 320 grams of ballast.

All the best with your build Dave and if you get a chance, click on the link I pasted above to see the photographs I took for you today.

All the best, Phil

[Peter Garsden]

If you look at my Hammer F3F blog you will see that I installed a 20mm ballast tube which I usually fill with about 4 35mm slugs of 19mm shower rail and lead. It flies much better. I have never flown it with a full 10 slugs, but it does need ballast in a 25mph wind

This is the blog - **LINK**

It flies in the lightest of wind with no ballast so is very flexible.

It does not match a mouldie and in a long high speed dive over the compression at the edge you can see the wings ripple.

So I say, put a strip of carbon down the entire length of the wing because it does need it.

[DAVE MATTHEWS 2]

Peter, I have emailed the creator Artur, who informs me he hasn't folded a wing yet. But I've bought the carbon, so it might have to have it lol.

Cheers, Dave

[Phil Elliott 1]

Hi there Peter. I fully agree with you on the first two points, I can see that you have enjoyed flying this model too.

I would'nt fly my hammer with a skin full of lead and I am trying to discourage Dave. You have loaded it up and paid the price - wing flutter! I hope you didn't break it.

Unfortunately you have introduced that hypothetical moulded glider into the conversation to bring everything into perspective! Which it doesn't. It adds confusion to what is a simple build.

I think that almost every pilot that flies a blejzyk will enjoy the experience. Lets leave it at that.

Dave seems to be a clever bloke, why not let him experience the plane in it's well refined form just the way it comes from Poland. He may well find, that he is happy with his model just the way it is. I certainly do.

I thought about adding some carbon to my wing recently simply because it has been hit by a 2.5m 3kg Wedge Tailed eagle. I know that the black stuff can add a bit of stiffness, but decided against it. The reason I didn't do it was that I couldn't remove the fibreglass and poplar skins to put the tow where it needs to be. (on top of the blank).

Just for the record I own a few composite models and enjoy flying those too. They are good at doing what they were designed for, but make a god-awful noise that disrupts the serenity of many slopes or paddocks that would otherwise be alive with the sound of birds chirping and friendly conversation.

I have been flying the clappers out of my hammer for two or more years now. Probably about ten hours fly time per week in strong wind. The wings that Artur makes are the strongest of their type and they are almost unique with only one other manufacturer using the poplar veneer.

If it is flown within it's limits it will never flutter. It flies as straight as an arrow. It penetrates in 40kts without ballast. How often do you get that kind of wind? As it comes from Poland I believe a good pilot could enter it into a competition and get better scores than the majority of pilots with a superior plane. A plane, by the way, that costs ten times the money, that will only out-fly a hammer if the pilot has skill.

All the best from Tasmania, Phil..........I don't know if you have seen mine fly so you can go here to have a peek.

[Phil Elliott 1]

Me again Peter. I just had a peek at your blog. I found it interesting. I noticed that you built your machine three and a half years ago. Is your hammer still intact and flyable? Phil

[DAVE MATTHEWS 2]

Guys, I am going to do it, because it wont add any weight and can't hurt. I don't expect to use the full ballast load( i have slopers that love that kind of thing). I have done it before by routing a 1.25mm slot in the wing,piping in epoxy and letting the blade in. Smooths off to a nice finish. Keep you posted !

[Peter Garsden]

Sorry Phil I thought I had replied. Yes the Hammer is still intact and has had very few mishaps. Easy to fly, easy to land. The only mishap I had was on Rushup Edge - famed for its Dynamic Soaring on Mam Tor Derbyshire, where there was vicious rotor as it was slightly off the slope which was flying northerly. It picked up the Hammer and smashed it into the ground causing the tail boom to break just before the stabiliser. I easily repaired it with an inner tube of fibreglass rolled on a piece of mylar.

[Phil Elliott 1]

Peter, I'm glad you got it mended.

I atomized my mefisto once by placing it on the ground whilst searching for my transmitter. It did a flip broke the boom and pankaked the V-bit. Ha Ha Ha.

Same plane got launched again shortly after the first incident only to turn it's self off as it left my hand on launch. Ha ha ha - that was my lucky day. It did a big circle of about a kilometer and then landed without scraping a wingtip!

All the best.

[DAVE MATTHEWS 2]

made a start on the first one. just skimmed the existing tow that comes from the joiner box to bind it all together. cutter is from set off pcb cutters from ebay.

[Phil Elliott 1]

Nice one Dave! I particularly like the dark heartwood of that piece of veneer with its peppering of birds eye.

[DAVE MATTHEWS 2]

Thanks Phil, top is the same and looks awesome varnished (pictures to follow)

[DAVE MATTHEWS 2]

Guys, are we using nylon wing bolts or ......?

[Phil Elliott 1]

I had difficulty getting the white 5mm nylon bolts into the embedded nuts, and they were so tight I screwed the knurled nuts out of the plywood wing bolt block in the fuz.

I think the bolts or the nuts are tapered, maybe both! ha ha.

Then I ran a tap through the knurled nuts and got some m5 bolts off ebay. But I must say, the ebay bolts dont break easily which can be traumatic.

The black plastic ebay bolts are a pretty good compromise I think as they are very secure and will break most of the time.

looking forward to seeing the finished product.. And to be honest I want to see a video of hammer crackin' it on the slope with a bit of lead in the belly!

cheers

[DAVE MATTHEWS 2]

Phil, I did toy with the idea of aluminium bolts by way of compromise. I have the same problem with the white plastic ones supplied. Just working on ways to get the rudder arm tucked away inside the fuse.

I'll keep you posted

[DAVE MATTHEWS 2]

fuse and tail feathers all done, with 20mm ballast tube (should be good for about 670g ish max.)

[Phil Elliott 1]

I can see that the hammer is coming along well Dave. You have your ballast well organised in short slugs and the opening under the inner nose is reasonably small too. It looks pretty 'dangerous' in the orange!

I had a dream nightmare last night. I think it was my mind's way of dealing with the frustration of builders apathy. I have been slack and really want to fly a few of the gliders I have bought. Last night whilst fast asleep, I opened up the box of a 3m carbon speedster I have been keeping under the bed. I showed it to a guy and when he handed it back the wing was rib and spar covered in second grade transparent film. It cost me $1250 and I was furious.

I decided to get on a plane with my faithful bull-terrier and visit the manufacturer in China who told me; "you get what you pay for". I got lost over there and my dog was almost taken by shark whilst scuba diving. In hung-foo province I had to sleep rough on the streets with european and american junkies that loved the place because it was cheap to live there and the drugs were everywhere. I was a 'fish' out of water. I decided to release my grudge on the model builder and come home but couldnt find the airport. A talking donkey told me it was only two blocks away, so I gave him a carrot to take me there. I was early at the check-in for once in my life and I was relieved to be heading home. I decided that I would build all my own planes from now on. I lived happily ever after.

Phil

https://www.google.com/imgres?imgurl=https%3A%2F%2Fvetstreet-brightspot.s3.amazonaws.com%2F20%2Fc8%2Ff15b9da54a70b1b731914381521e%2FBull-Terrier-AP-9QDKHP-645sm101513.jpg&imgrefurl=http%3A%2F%2Fwww.vetstreet.com%2Fdogs%2Fbull-terrier&docid=dYzQ5ovotP2bfM&tbnid=3JZcKNOiRx4VAM%3A&vet=10ahUKEwjIvue1qp7fAhVRVH0KHZw8C_sQMwh1KA0wDQ..i&w=645&h=380&client=firefox-b&bih=427&biw=865&q=bull%20terrier&ved=0ahUKEwjIvue1qp7fAhVRVH0KHZw8C_sQMwh1KA0wDQ&iact=mrc&uact=8

Edited By Phil Elliott 1 on 14/12/2018 03:08:27

[DAVE MATTHEWS 2]

Phil, cut down on the caffeine at night-time bud! I thought I had weird dreams lol. Just got the second wing to wire up, then it's wait for the right conditions time.

[Phil Elliott 1]

I just read that again, it is a bit strange! But it made sense at the time! Ha ha ha. The mind, and especially the subconcious mind, is an incredible organ.

Moving along now, I have just repaired the wings on my Hammer and it should be in the air in the next few days. I also fixed my 3340mm Graupner Discus and she's up and running again too. The wind has been very strong down here and variable in direction. I am hoping it decides which way to blow over the weekend so I can plan a sortie.

Keep up the hard work on the model, it is definitely worth it. - P.E.

[DAVE MATTHEWS 2]

moving on, decided to use multiplex mpx connectors to keep wiring simple and tidy. A handy hint (probably from this site somewhere), to pot the connectors with hot melt. Not only does it prevent flex and eventual failure at the solder point, it provides a good grip . I didn't use a mould (haven't got one!), just pump the glue in there then, while it's soft, form it with a couple of bits of aluminium flat bar. Not as tidy as a mould but hey.... cheaper lol.

[DAVE MATTHEWS 2]

DONE!! Sadly the nose came out dark because I only had grey primer (needed white), but that can be resprayed easily enough later.

[Phil Elliott 1]

Nice work Dave. yours looks like a different model compared to my V-Tail version. The colours on the extremities will help to keep you in touch visually against the blue sky or grey clouds.

I would love to see some footage from a 'Head-Cam' once you get it balanced and start using a bit of lead.

Cheers, Phil