Berkut Canopy hinges wanted

[TMann]

Foundries have been casting aluminum using the "Lost Foam" method since they were able to touch their index finger with their thumb.

As far as the alloy used ........ it is the same as that specified in the Berkut drawings. I didn't do the fancy tooling so mine is a bit thicker in places but you would be hard pressed yo find the differences when placed side by side.

 

PS: If you want to try this for any parts and can't find a foundry that will do it, check with your local artist's co-op and find someone who does metal sculpture casting.

[Jon Matcho]

T, you continue to impress with your ingenuity.

 

My initial inexperienced reaction when I hear "foundry" is that there's some guy in a blacksmith apron who just melted down some old lawn chairs, antennas, pots, pans, etc., and will have no problem pouring your hinges. My concern would be the resulting strength of the parts.

 

Also, here's an article on the grades of aluminum that may be of interest to you.

 

I am not saying this is a bad idea. Quite the contrary, so let us know how it works out.

[TMann]

In the Berkut drawings it stipulates Aluminum 356. This is the only alloy they pour there. I took my pieces in yesterday over lunch and the guy told me that they had the furnace down at the moment (i.e. shut off) otherwise they could have poured them on the spot.

 

We had a guy in our EAA chapter that really set the bar when it came to ingenuity. He was building a Curtiss P-6 Hawk. The only part he found (of an original plane) was a wing and he found that in a jungle in Central America. The parts he could not buy he machined himself then he sandblasted them to give them the appearance of being cast.

After a few personal setbacks, he donated it to the EAA museum to prevent creditors from getting it.

 

Anyway, when you have folks like that in your chapter you learn that most any problem has a resolution.

[TMann]

I asked the foundry to hold off on the pour until I get some new forms to them. I used some blue extruded styrofoam and cut some more shapes Saturday. The blue foam sands and machines better. Now it's just a matter of whether or not they can pour with this type of foam.

 

I'm hoping to have a couple of aluminum hinges by end-of-day tomorrow.

 

Hey Tony ........ are you going to need a couple of these?

[tonyslongez]

Yes I am my friend they look great. Nice job T-MAnn. How much and where do I send the money.

 

Tony

[tonyslongez]

T-MAnn BTW I have those hinges in A-Cad and solid works if you need it let me know. I'm going to try to digitize the entire landing gear system in 3-D autocad. this is going to be fun fun.

 

Tony

[TMann]

The plans also go into great detail as to the layup of the gear legs in CF.

[mak790]

I'm going to try to digitize the entire landing gear system in 3-D autocad.

That's a great idea Tony let me know when you finish, I'll be happy:) to do a simulation of entire landing gear system in Autodesk Inventor 11 or 2008.

Similar to my last project.

[tonyslongez]

Mak

 

Great work. I think we are going to have alot of fun with this.

 

Tony

[TMann]

Well, I went to the foundry over lunch taking all of my styrofoam blanks. They poured 4 of them and while they worked in theory they were less than perfect. The shape of the hinge caused it to twist a bit as they cooled.

 

Another option would be to make one out of wood with a slight bevel towards the middle ( which would explain the shape of the orginal hinge drawing.) I'm kind of weighing this one. If I was going to make a bunch of these, this would be the way to go however for 2 hinges the effort seems to be a bit questionable. I may go back to my plan of cutting them out of a billet. In reality, the 6061 billet would carry more strength than the 356 alloy.

 

If I did go the wood model route, I would have a ton of control over the finished shape, smoothness and other fine details.

 

For now I'll work on my canard and ponder it a bit more.

[mfryer]

Back to the drawing board.

 

Its things like that that make me excited about building an airplane. If it were all so easy, there would be little satisfaction in completing the project.

[Cozy1200]

>Well, I went to the foundry over lunch taking all of my styrofoam blanks.

 

I curious, what did it cost you to have them cast?

[TMann]

>Well, I went to the foundry over lunch taking all of my styrofoam blanks.

 

I curious, what did it cost you to have them cast?

Seeing as none of them came out ..... zero.

They quoted me about $50 each

[tonyslongez]

T

 

Unfortunately the design for the hinge that you have is old.

Dave came up with a new hinge design that was easier to make than those.

let me do some work on the A-Cad and see if we can't come up with a suitable two piece hinge.

 

Tony

[TMann]

Hey Tony,

I'm picking up a 12 x 2 x 8 inch piece of 6061 after work. I can cut the profile from this (times 2) to come up with the full 4 inch width. This actually may work out better in the long run. I wanted to add a latch lock to the back of the pilots hinge to lock down the passenger canopy when th pilots canopy closes.

Now I can do that as the 2 hinges don't need to be the same. I'll have these made this weekend and will post the pics.

[tonyslongez]

T-Mann

 

Go to the Berkut section of the forum and see what we have proposed for the canopy hinges.

 

Tony

[tonyslongez]

I was wrong here it is. your gonna like this

 

http://www.canardzone.com/forum/showthread.php?t=2092

[mak790]

T-Mann

 

Check this site (as a reference) it's about home casting. This same method which you were going to use.

http://www.matus1976.com/akira_bike/content_14_09_07_update.htm

 

 

Mak

[TMann]

Check out this 3-D rendering in aluminum 6061-T6.

I'll spot weld the 2 pieces together to get a 4 inch wide hinge.

By working with the 2 inch material I saved about $200 on the whole deal.

 

The weight of one four inch hinge before boring and cutouts s 2lb 3oz.

 

Actually, if I had known it was going to be this easy, I'd have started this way.

[mak790]

It will be a lot of work to get the final shape after welding, 6061-T6 is highly weldable but the properties near the weld are those of 6061-0 (for example 6061- 0 tensile strength no more than 18,000 psi and for 6061-T6 tensile strength at least 42,000 psi) of course hinge won't break but I believe that "parts hinge" is strong enough and it looks much better but that's mine opinon.

Check that webpage it's about welding 6061-T6

http://www.thefabricator.com/AluminumWelding/AluminumWelding_Article.cfm?ID=1458

btw Have you seen James Redmon's hinge it's even easier to make.

http://www.berkut13.com/canopy27.jpg

[TMann]

Yeah ....... I'm thinking that the two pieces really don't require being welded.

The CF hinges that James made look real nice ....... however, Berkut tried this and rejected it as a viable hinge. (Reasons unknown.)

 

I'll have to tap an extra connection point so 4 points where the canopy bolts on vs. 3.

 

It only takes about 30 minutes (or less) to cut one of these out. I keep a bucket of ice nearby to cool the piece from time to time (easier on the fingers.)

 

Your hinge rendering looks real good. I would guess it would take a bit longer to make but it really looks 'aircraft' all the way!

[mak790]

I would guess it would take a bit longer to make

Actually I thought about laser or water jet CNC staff. I was in similar situation few years ago when I was building my car. I thought about bend saw or angle grinder but finally I found a garage with laser cnc. I gave them material and 2D drawings next day I paid 15 or 20$ and I was amaze about quality of these parts. I believe that cutting all parts won't cost more then 30-40$.

 

Mak

[TMann]

Actually I thought about laser or water jet CNC staff. I was in similar situation few years ago when I was building my car. I thought about bend saw or angle grinder but finally I found a garage with laser cnc. I gave them material and 2D drawings next day I paid 15 or 20$ and I was amaze about quality of these parts. I believe that cutting all parts won't cost more then 30-40$.

 

Mak

I think there is a place here that does that. Wished I had thought of that.

[mak790]

Ok my last 5 cents in the hinge discussion.

In my opinion you should use two bolts to connect these parts I think this is the best way to do this. If you use these bolts close to the hinge fitting points you don't need to worry about anything.

Bolts in the middle max stress 31000 psi 300lb force

Bolts close to the fitting points max stress 18930 psi 300lb force.

Without bolts max stress 16210 psi 300lb force

I used ,250 bolts in these analysis.

 

But because I'll have stress analysis next month in my school I'm not 100% about it maybe someone else can confirm this.

 

(Sorry Jon for so much picture in last week but I belive one picture is worth more then 1000 words I won't post more)

[Jon Matcho]

(Sorry Jon for so much picture in last week but I belive one picture is worth more then 1000 words I won't post more)

What?! Don't be sorry -- this stuff is awesome! You've done a great job here. Post as many pics as you like. I'll get another hard drive to support, or increase allowable files sizes, whatever.

 

Good pictures are easily worth 1,000 words and definitely make reading more clear and enjoyable.