Fireproof aileron tubes Long EZ

[Hank Clark]

I'm looking for some advice on replacing those aluminum 1/2 inch aileron tubes with 4130 steel.  Do we use the same .035 wall thickness as the aluminum?  And those rod end bearings too,  I have new XM-3 bearings with the 1/4 inch threads.  Do we thread them into aluminum inserts, or use steel inserts?  I understand that steel inserts with a collar were used in later design Longs, but I don't find any info about them.
     I sure hope I can find somebody who has done this and has all the answers.  
    Thanks..........

Hank

[Anonymous]

Hank! I'm all for you doing the mod that you want but I'm curious what is wrong with the aluminum? If it's a strength thing you are worried about I would use either titanium, or,  have the aluminum heat treated most all of the 2000 grade aircraft aluminums can be heat treaded this will give you more strength without compromising weight. you can certainly use steal but I think you may find it will tend to corrode, it's also very heavy. As for the rod end bearings if you have a lathe you can turn down the linkage to accept a quarter inch thread for a female rod end bearing or if your stock is large enough drill a hole and tap it for a male rod end. I'm not sure which is better . I machined all my linkage for the aeileron out of titanium and used female aircraft grade rod end bearings, lite, strong, non corrosive. Very trick. Make sure the rod end bearings are aircraft grade. They are rated whith a higher thrust load than non mil spec rod ends.

Good luck! Tony

[Hank Clark]

Tony-
There was a mandatory ground in the 'Canard pusher' a few years ago advising EZ owners to get rid of any aluminum in the engine compartment in case of fire.  I really don't want to make this modification because of the added weight, but Rutan said replace, so we replace...........

[Tony]

Hank! thats good to know. Can you recall was that in the CP? and if so which page? I may have missed that. When it said "all" it meant all brackets as well as bell cranks? or just the tubes?. Titanium is a little hard to machine but I will machine everything out of titanium if I have to. or (stainless)

Thanks! Tony

[MacGyver]

Regarding heat treating 2000-series aluminum alloys:  If the information was meant to infer that one could make existing aileron tubes even stronger by heat treat - bad answer.  If the tubes are made from 2024-T3 (as they should have been originally), there is no way to ever make them stronger by additional heat treat - in fact, they will never again be as strong as when in the "from the mill" -T3 condition.  For one to take this suggestion a different way, and start with tubes in the "0" condition, the best you will get is the T42 condition, which is not quite as stout as T3.  Most "aircraft" aluminum alloys will have better conditioning from the mill, versus heat treats in the field.  "0" condition is specifed where some requisite of manufacture (e.g. forming) needs to be done prior to heat treat.  A good example on our airframes are the hinges on the GU elevators - they start out as 2024-0 and are then heat treated to the T4 or T42 condition after forming.  They are not, nor will they ever be, in the T3 condition (as has been erroneously given in the plans, as I recall).

Stay away from your own attempts to heat treat your aluminum components if they are "per plans" - there is no good reason to do so.  As for fireproof controls, that information is in the CPs.

-Joe Person
Tech Counselor 4418

[TIM BAILEY]

Hi Joe...Did the CP replace the ali control rods or was fire resistant paint the recommendation?

[Hank Clark]

The Canard Pusher was number 49 page 6.    They recomended steel tubing and painting the firewall with fireproof paint.   By the way, I have an extra quart of the paint if anyone wants to buy it.  They only sell it by the gallon.

Hank Clark