Bearhawk s/n 1050

Designed by engineer Bob Barrows, the BEARHAWK is being built in many countries around the world.

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Jayson v Schalkwyk
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Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Thu Jul 02, 2009 4:15 am

Hey there guys,

Here is a link to my Expercraft website which shows the early days of my construction. Go in and have a look and let me know what you think.

http://websites.expercraft.com/jaysonv/

I have a topic under the general forum aswell, and will see if I can get the mods to move it here. Bear with me if updates are a bit slow - am trying to finish up with ATP subjects then a flt test.

HD
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Re: Bearhawk s/n 1050

Unread post by B.hawker » Mon Jul 13, 2009 8:12 am

Hi Jay,

Great to see you're progressing!! I must come around and see your project sometime!!

#870 is getting there, I have completed the fuse, tail, gear and controls, just done the firewall and now busy with tabs for the floor etc. Soon Ill be able to sandblast and test fit the wings. (the fuse looks ugly at the mo because of the bare metal)

Keep bending those rib attach angles..I remember them being a bit of a pain the arse (loads of them!!)

(tried posting a pic but my connection is no good)

Cheers
B
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Jayson v Schalkwyk
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Wed Sep 16, 2009 8:52 am

So, progress has been slow in the last while. What with a sick girlfriend, 1 ATP exam still to go and just general other stuff going on, I havnt been in the garage nearly as much as I would like. Also, dont expect progress anywhere near as quick as the Prolific hombuilder Rudi, he is doing a great job!!

But I have managed a few small items. Rib angles are used on the rib structure to give the rib some stiffness and in certain places, the angles will be used to attach the various sections of ribs to the different spars, main spar, false spar (just behind the fuel tanks and then the rear spar. The angles used for the stiffness are made of 0.025 2024 ali, and where the ribs attach to the spars of 0.032 2024 ali.

Tried to attach some pics, but the files are a bit large, will try make a plan then get back to you.

Jayson
Last edited by Jayson v Schalkwyk on Thu Sep 20, 2012 9:36 pm, edited 1 time in total.
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Fri Sep 18, 2009 8:50 am

Took some pics in a smaller format.

This will show the stages of a rib angle, from 1inch wide strip, then bent to 90deg then drilled and deurred.Other pics will show the center rib with angles not yet riveted on and then a pic of the aileron with its 'pocket rib' which will attach to the rear spar.

There are 3 spars, main, false spar (fits in behind the fuel tanks) and the rear spar. Last pic shows just how many ribs there are, 170 in all

Thats it for now.
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Re: Bearhawk s/n 1050

Unread post by Bombardier » Wed Nov 18, 2009 9:02 am

Any more progress Jay? :)
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Thu Nov 19, 2009 9:39 am

Now that those bloody f^%$^*^%^&ing ATP exams are out the way, and am testing tonight, hopefully after friday lunch time when I have a little green book :D :D :D :D progress will be fast and furious.

Thanks for checking though bugger.

HDriver
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Tue Feb 09, 2010 1:53 am

So, been in the shop recently.

To get started I needed to mark off all the rivet locations on the wing ribs. The rivets are spaced evenly at 1.5inches all the way around the different ribs. Took me a little while to work out where to start but the Bh email list guys pointed me in the right direction. In between each of teh rivet locations, the builder needs to 'flute' the ribs.

When you creat the flange on the rib, the rib tends to bow down the length of the rib. Fluting is a process whereby you effectivly shrink the inside diameter of the rib and this then 'pulls' the rib straight again. You start off with small flutes intially, and keep at it till the rib lies flat on the workbench. Its a slow tedious process. I started off with the 46 nose ribs, then the 22 center ribs, and all of the flap and aileron ribs.

More to come...
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Tue Feb 09, 2010 2:24 am

So, back in the shop again.

This time it was on to the center ribs, but same process as nose ribs. What I forgot to mention is that after the fluting you have to recheck that the flanges are at 90deg. I hald it up against a small jig and beat the flanges with a plastic mallet. This is so that the rivets will all line up nicely when I eventually get to skinning the wing.

Once I got the center ribs done, I moved onto the smaller flap, aileron and flap nose ribs. The aileron nose rib needs a 3/4inch hole drilled into the leading edge of some of the ribs. A balance tube will fit in the hole. The balance tube is 3/4 in aluminium tube that gets filled with lead and will balance out the weight of the aileron, forward of the hinge line.

Back to nose ribs. Was time to drill more holes. I had previously made some rib stiffeners. These are just 1/2inch by 1/2inch 0.025 2024-t3 ali strips that get riveted onto most of the ribs to prevent the ribs from warping. In all, there are about 350 stiffeners to go on the various ribs. Each nose rib gets 2 stiffeners, 1 0.025 for strength and a second one of 0.032 which is where the rib will be attach to the spar. I drilled the location for the 0.025 stiffner. There are 4holes per stiffner and 46 nose ribs - 184 holes in all. Once drilled, remove the cleco and start deburring both sides of each hole.

All in all, wasnt bad. I got my little woman to help at one stage and this did make the hole drilling go a little faster. I would drill and she would insert a cleco. This is to 'match drill' the stiffners so that they fit exactly right when it comes time to rivet.

Till next time.
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Aileron nose2.JPG
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Re: Bearhawk s/n 1050

Unread post by B.hawker » Tue Feb 09, 2010 6:51 am

Howzit Jay,

You're making FANTASTIC progress - well done, soon you're going to have a wing to be proud of.

You must come around sometime and take a look at #870, Im busy with the interior now, she's getting two new MGL Voyager's (awesome product from SA) and hopefully an O-470-U

Keep up the great work.

Cheers
B
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Re: Bearhawk s/n 1050

Unread post by billyjoe » Tue Mar 09, 2010 10:39 am

come come you lazy bugger, i know things have been a BIT busy but its time to get back into the "Shop" and do some work on 1050. after all, i'm gonna need to do my ab initio on her asap!

see you soon
b
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Re: Bearhawk s/n 1050

Unread post by billyjoe » Sun Jul 11, 2010 3:34 pm

still no progress?? whats going on HD, whats next to do in the shop?
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Sat Sep 18, 2010 3:25 pm

So a little while ago I got some more BH work done. I spent the day at the company sheet metal shop and got quite a bit done.

Started off by scotchbriting and cleaning the nose ribs. Scotchbrite is a very fine emery type material (similar to the green stuff on the sponge you use to clean dishes) that lighty 'scratches' the ali - thereby creating a good surface for the alodine and primer. I use acetone to remove pen marks, any oils or greases from the ali. This is just to ensure that its clean prior to starting the alodining process. I also cleaned and prepped all the rib stiffner angles. There is 1 stiffner per nose rib which will get riveted in place. The rivet holes have already been drilled and deburred. This taught me th emeaning of elbow grease again.

Alodining is the chemical application of a protective chromate conversion coating on aluminum. The rib was then placed into a alodine solution for a about a minute, the dipped in some water to rinse and allowed to dry. Then, repeat 45 other times for the other nose ribs. Quite a laborious process, but quite satisfying. Once I had done all the ribs, I did the same thing for all the stiffeners, but 5 at at time so save time.

Once home, I started assemblying the stiffners to the nose ribs. The stiffners are held in place by solid MS20470-3 rivets. These rivets are still small enough to be squeezed by hand instead of by rivet gun. Went quite quick once I got the hang of it but did still make a few duds - which needed to be fixed later.

Have pics, but too large to post here, so once I have worked out how to make them smaller, will post them.

Jayson
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Sat Sep 18, 2010 4:29 pm

Here are a few pics of the riveting sequence of the rib stiffners.
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Sat Sep 18, 2010 4:56 pm

So with the nose ribs done and out the way, the next thing to do was drill a 1inch hole in the first 5 of the center ribs.
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I had searched for quite some time to get a 1inch step drill. I could get one here in SA, but the bit would cost about R850, so ended up buying the bit while I was in the UK on a charter. A step drill is really nice, in that it deburrs the hole to the next size of step. I found it was easier using a step drill than a hole cutter.
Step Drills.JPG
The reason for this hole is that this is where the flap drive actuator will route through the ribs behind the fuel tank. Rib1, is actually 2 ribs riveted back to back. The intial plans called for only 1 rib, but after a wing stress test was done, a second rib was added here. The first 5 ribs are of 0.032 thickness, 2024 ali and the rest are 0.025.
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This rib is the short rib, and fits in behind the fuel tank and false spar.
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Till next time
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Re: Bearhawk s/n 1050

Unread post by Jayson v Schalkwyk » Fri Apr 08, 2011 12:19 pm

So, long over due!!

Was having Bearhawk building withdrawl symptoms and so after being away awhile flying etc I got a started again on my plane building. Must admit, it helps having access to the WWW and being inspired to keep going after seeing other builders progress. Was nothing exciting but still some progress. Took some of the rib stiffners (scroll up to see what they look like) to work and scocthbrited and alodined 2 sets (different lengths) or stiffners. Was tempted to bring some with on my charter flight, but didnt want 5L of alodine leaking out in the Lear baggage bay:oops:

So, have decided to make a concerted effort to just do a little each day. As the saying slowly slowly catch the monkey. After making small parts, eventually they will all fly in tight formo one day. Will add some pic later.

Jayson
Last edited by Jayson v Schalkwyk on Thu Sep 20, 2012 9:38 pm, edited 1 time in total.
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