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Hammer F3F

The one thats tempted me back

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Rob - Flying Dog RC16/11/2012 16:38:13
19 forum posts
6 photos
Posted by Tom Satinet on 16/11/2012 15:47:18:

Is that the lengendary P4000 TX i spy next to the Hammer?

The one and only!

It just so happened that it was maiden for them both - TX and the Hammer

I was hunting one for ages ....

PS. How's your Duo ?



Simon Cunliffe16/11/2012 21:06:33
163 forum posts
10 photos
Posted by Rob - Flying Dog RC on 16/11/2012 11:17:17:

Hi Simon

manual : **LINK**

Covering - That's up to you realy - I'm happy with Oracover - appart from the wing tip edges is was piece of cake to do.

Hinges on the wing were not covered - but I think it can be done on the top side - tail hinges are covered (see my picture earlier in this thread )

You might go for Varnish - some people like flying furniture - does the job - looks different.

Glassing is also an option.

Only one thing I'd do different with the Hammer is that before Covering I'd put 1 layer of Varnish - and then sand it with 320grade sand paper - to get rid of all the little fluffy bits - but that's purely for visual effect, when you look from 2m distance it will make no difference

How it flies? It's one of those models that if I crash it - I'd build another .

PS. Ballast tube should be installed before gluing the nose in - otherwise it's akward to do it later.



Edited By Rob - Flying Dog RC on 16/11/2012 11:23:12

Thanks for the link Rob : )

I probably will use Oracover but I'm still wondering just how I apply it.

I'm thinking starting with the bottom side from the trailing edge spar and wrapping just round the leading edge then from the leading edge over the top side going over the ailerons and flaps and then covering the underside of the ailerons and flaps. I suspect I'd have to cut through the Oracover where the hinge is (top side).


PS I hope that makes sense, it's Friday night and have had a glass or two of wine

Rob - Flying Dog RC16/11/2012 21:51:55
19 forum posts
6 photos

Start with the bottom - from the leading edge towards the trailing edge.

Leave some on the trailing edge not attached - secure with some tape so no dirt will go in. That will overlap the film that will go over the trailing edge. Top side - as you like - I'd start from the leading edge.

If you want to cover the hinges in the wings - then of course first you need to move the flaps/ailerons as low as possible - while covering this part - be carefull with the Iron - if you shrink it too much - movement will be limmited

Some test will be best for that part - hard to explain - some ide will give you covering the tail parts.

Hope that makes sense - It's Friday night and still didn't opened my beer :D



Simon Cunliffe16/11/2012 22:03:57
163 forum posts
10 photos

Cheers Rob... go and get that beer!

Rob - Flying Dog RC16/11/2012 22:26:44
19 forum posts
6 photos

Oh - and of course the top side covering must overlap the bottom one (leading edge) - this will be the part of covering that will drive you crazy on the wing tips - to work out nice finnish without to many wrinkles ..

Rob beer

Simon Cunliffe02/12/2012 12:42:19
163 forum posts
10 photos

So I'm still pondering the best way to cover the Hammer, I've attached some photos and hope you that are more experienced at this sort of thing can give me some advice.

My thoughts have been I could just varnish the wing, however would this provide enough protection to the odd less than perfect landing? There are some balsa bits inside the recessed areas, how would a water based varnish affect the balsa? Should I really use some lightweight fibreglass as well? If yes how would that work with the live hinge?

Covering with Oracover/Profilm will the edges lift around the trailing edge of the ailerons and flaps causing problems when you least need them?

Any other suggestions on how I could cover it without adding too much weight?



Tom Satinet03/12/2012 09:09:05
516 forum posts

whatever covering you do use, I would plan for some visibility.

Especially on the wing tips and underside - i.e colours.

Simon Cunliffe04/12/2012 06:03:48
163 forum posts
10 photos
Posted by Tom Satinet on 03/12/2012 09:09:05:

whatever covering you do use, I would plan for some visibility.

Especially on the wing tips and underside - i.e colours.

Definitely, it's a horrible feeling when you loose orientation : (

Trevor11/01/2015 15:03:32
365 forum posts
52 photos

I know this thread is a couple of years old but I'm about to start on a Hammer build and am hoping I can revive it for a bit of advice along the way.

I want to build this model primarily for slope flying but also with the electric option. The instructions show the inner nose cut off quite short, and the electric motor mounted in the alternate sheath nose. However, I'm tempted to mount the motor in the inner nose, and leave the motor, ESC and power pack in place. For slope use, just the prop and spinner would be removed and then the nose sheaths swapped over. This isn't something I've done before though so I'm worried that there may be some fundamental snag with this arrangement which I've overlooked!

Any thoughts on this (or any other aspect of the build for that matter) would be much appreciated.



Peter Garsden09/07/2015 17:46:49
1528 forum posts
1095 photos

Hi chaps - I know your blog is 3 years old, but I have started my own here -

I agree with everything you have all said - this is the best build blog on the web for the Hammer, and I hope I can contribute something new with mine.

I notice that some of you have a cross tail. I have a V Tail. I notice there are no pictures of the links between the control snakes and the clevises at the tail. Curiously the kit doesn't come with any clevis but there are some horns. I am presuming that ball link type horns are the order of the day such as

Ball Link

The bolt will go through the hole in the horn, obviously. The problem is that the snake inner wire is very thin, and I can't work out what sort of attachment will work. All the holes in the clevis I have found seem to be a minimum of 2mm. So why no clevis is supplied puzzles me? Rob have you any idea?

I agree that inserting the wing joiners is a devil of a job. I had 3 goes at sticking the tube and steel bar into position so it wouldn't move. Even worse was trying to get epoxy past the bar and tube to fill the gap. I tried a syringe but it kept getting an air lock in it. It was a nightmare. In the end I just used a glue spatula which I trimmed down to fit the width of the tube.

Will be filling up the gap again tonight with even more epoxy.

I can see that the hardwood blocks might be tricky so I will be using my pesky hot wire pen which is a brililiant invention of Ivan Bradbuy frorm our Leek and Moreland club - you chaps are all welcome to fly with us if you wish - check it out -

This is an image of something similar but I made my own out of a piece of balsa with two pieces of wire attached to the edges wrapped in masking tape and two bits out of a household plug to hold the thick and thin wire. Works a treat

Wire Pen Cutter

Anton Huber23/10/2016 21:04:10
2 forum posts

my Hammer is meanwhile flying . was fun to build and is fun to fly
Phil Elliott 102/06/2018 08:44:15
17 forum posts

Greetings earthlings

I just ordered a new set of wings for my hammer. While I was at it, I ordered a Pirat and a Duo for the summer breezes. Yes, we get a real summer down here in Tasmania! Also we make proper beer, unlike you poms. And don't get me started on the cricket.

On the serious side of things, The hammer. I think it is good to take some time working on those stiff hinges. It is a very difficult task for someone like myself that was bought up on a diet of rib and spar wings with 20% thickness and a balsa trailing edge.

Loosening up Arturs hinges is a serious challenge for us all. This task in itself can make or break the model. Here are my thoughts on doing the job.

continued on next post.....

  1. Think about it for a while, explore the architecture of the joint and don't do anything for a week or two.

  2. Don't look at the flap as just a flap that goes down, even if you intend using 5mm reflex up travel, think again. If you decide to mix aileron to flap later on you need to prepare for that deflection before you even strike a blow on the hinges. Try to think of your flaps as ailerons that travel even further down.

  3. It is my not so humble opinion that the hammer can have too much flap travel. I have stacked mine a few times because on a windy day, no ballast and a poor (too high) approach I have panicked and pulled the throttle stick right back (flaps down 60 to 80 degrees) every time I do it the model is disturbed from its gentle glide path and stalls - even with the linear proportional down elevator mixed in. This is because ( I think in my tiny brain) that the mixture of down elevator should be exponential and not linear. I need to use a five point curve on my mix and not a three point straight line. I think I just confused myself, so don't feel bad if you didn't get that. To remain on the safe side, if you are going to fly the model at it's minimum weight as I do, then plan on about 25-30 degrees down travel. This will pull the model up in no time and maintain a good glide path if mixed with 7% of linear down elevator in the mix.

  4. Don't touch the wing yet. think about it a bit more. How are you going to make those sturdy hinges bend? They don't flex when you get the wing, so you have to do something to free them up. This is the really hard bit. Eat a stack of weet-bix for a few days to strengthen up your fore-arm and shoulder - those muscles will come in handy next week when you commence the work.

Phil Elliott 102/06/2018 08:46:12
17 forum posts
  1. O.K. Its time to free up the hinges. Clear the cereal bowls from your workbench and prepare your mind for an arduous and frustrating job. Meditate for half an hour - in your minds eye you should see a mega slope with lush grass and plenty of women retrieving the models - then wake up and get a grip of yourself.

  2. Get a half dozen 1/4 sheets of aluminium oxide or garnet sandpaper of good quality, that's four pieces of ~ 120 grit and two pieces of 240 grit for each wing. Fold the quater-sheets into thirds so that they have two rigid abrasive edges.

  3. Gently move the flap/aileron down a bit to observe the hinge line on the top of the wing. Look before you even think about sanding. Look again after moving the surface up a little and this time look underneath into the groove to see where you will strategically apply the hard edge of the folded sandpaper by using long strokes.

  4. Start sanding the hinge line, but do not sand the kevlar tape. This is a very difficult and frustrating task because the wood is hard but the kevlar tape is very soft compared to the poplar on the top surface and even the balsa below. The sandpaper gently works it's way through the wood but you can potentially sand through the kevlar in four or five strokes. With this in mind, sand for a moment, dust it off, take a peek, then start again working slowly and checking all the time to see the effect on flexibility of the joint and the surface deflection. STOP before you go too far. If you think "I might need a bit more travel, I'll just give it another go" then quit that stinkin'- thinkin' and refer to your notes from stages 2 and 3 about minimum/maximum travels. At this stage you have earned a beer, so take a break.

  5. The hinges will never be easy to move. Learn to accept this fact. Factor this knowledge into your servo selection. You don't need to spend lots of money to get a good servo, but you will need to do a bit of research on them. You should really use micro 17g mg servos or 25g thin wing servos with mg for the job. I would go for a servo with at least 4kg rating. You definitely need a good bush or bearing inside the gearbox as well because some servos just rely on the plastic housing, those servos will work well for a while and then they will expire before their 'use by' date.

  6. Remember that the hinges will improve with age, or as Mr. Humphries said in the TV series "are you being served?' - "They'll ride up with wear".

  7. Finally and very importantly also. Don't brush your varnish into the hinge line underneath the wing or on top for that matter. It will definitely muck up all your hard work. On that topic also; If you are covering your wing with film, I would suggest using two pieces of film top and bottom. Use a long straight edge to cut the film so that you can start 1/16" away from the hinge line and go from there. leave the hinge line uncovered then when you finish covering use some water based paint and an artists brush to hide the gap. Thin it down by 20% so that it doesn't gum up the groove.

  8. Give yourself a pat on the back because your live hinges will last a good while and ensure accurate centering and no slop. Conbine this with their ability to reduce drag and know you have a slick glider. My hammer is very quiet even in a zoom.

Thankyou for reading my guide to blejzyk live hinges. All the best, Phil Elliott

DAVE MATTHEWS 228/11/2018 15:29:51
63 forum posts
38 photos

Hi, has anyone thought about setting a 6mmx1mm carbon blade along the span? or doesn't it need (overkill), I do intend fitting a 20mm ballast tube.

Phil Elliott 128/11/2018 16:31:28
17 forum posts

Hi there Dave. I have never taken mine to that level. I have given it a good 'hammering' though - to coin an old phrase.

I do know that there is a fair bit of tow in the centre section of the wing because I can see it if I look at the surface on a low down level. You, can probably see where it is by shining a super-bright LED torch through the wing to reveal the black tow. I would imagine that there is a length top and bottom along the thickest part of the section from root to tip also. It might be ok to add more, providing you don't interfere with the servo wire channels or servo pockets. Nor would I align top spar with bottom. Stagger the spars a little if you are going to use one on top and one underneath. 6 x 1mm might be ok, but if I were going to do all that mucking around I would go to hobbyking and get a bundle of their 6 x 2mm pultruded bars - I think they come in 750mm lengths. These carbon bars are the same as the ones they use in the bix3.

I have done a similar reinforcement on several foamies in the past. I just tape a straight edge onto the wing, and use my dremel with a router bit of the right width to make a groove. I always use polyurethane fizzy-glue to glue the pultruded rod/bar into the slot (gorilla glue is one such product). Polyurethane glue gives a flexible bond with the epp. and should not melt the polystyrene either.

One down-side to cutting a slot into the wing surface is that it will probably decrease the resistance to twisting that the underlying fibre-glass gives to the hammer. Mine has p.s. foam, then a fine cloth and then the poplar.

Here is a link to an amatuer video of my beloved hammer. Cheers, Phil

DAVE MATTHEWS 228/11/2018 17:28:57
63 forum posts
38 photos

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 228/11/2018 17:35:43
63 forum posts
38 photos

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 129/11/2018 04:24:33
17 forum posts

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 229/11/2018 07:41:09
63 forum posts
38 photos

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 129/11/2018 09:52:05
17 forum posts

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

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