No. 3 build ready to kick off...

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If the aluminum is heat treated...there are probably still micro-fractures. In a perfect world you would want to anneal, bend, and then heat treat. However, heat treatment ovens big enough to accept a bicycle frame are very expensive.

Jason
This was my first thought also. My concern is that even though it appears to be successful, the earlier failures prove that it does not bend without fracturing. If the tube is just short of failure, what will happen later when it is under stress from a vibrating engine? This is why it is never advisable to cold set the stays on an aluminum frame. I'm not sure what your DIY options are.
 
Non heat-treated aluminum is not common on the consumer market. I have annealed T6 6061 (IIRC) the ghetto torch way for non-structural use and it was a pain as it would work harden easily and I ultimately went another route. I'm by no imagination an expert, but IMO, I'd use steel for hand forming, especially with the speeds and extra weight of a motorized bike.

Love the design, though!
 
I'm new to all this - it's my first frame build - so I hear what you guys are saying.
When forming these bends during my first and second attempts, I soon found I could 'feel' when I was applying too much pressure to the bender's lever. Looking close up, I could also see the metal begin to 'pucker' at the bend shortly before it began to fracture. That's why I figured it was sensible to relieve the bend radius and go for a more generous bend to eliminate both these factors. During my third attempt, I didn't have to exert excessive force and no evidence of puckering occurred during the forming process.
After both my first two attempts at forming the downtube's lower bend failed, I was contemplating a Plan B, namely to use my Gnome & Rhone 125cc motor as a stressed member as intended in its original motorcycle frame design. In this format, the frame downtube terminated immediately below the front motor mounting bracket. There was no frame extending below the motor. I thought I may have to go with such a design and maybe insert a cosmetic, ie, non-structural, section of steel frame slung under the motor extending back to the bottom bracket.
Having successfully - or so I thought - formed the downtube from aluminium at my third attempt, I thought I could dispense with the Plan B idea. But now I'm having doubts... Hmmmmm
 
Gnome & Rhone, the old TOC aircraft rotary engine manufacturer?! That's awesome!
 
If you do a motor mount setup like TRM did (Project Chris) in addition to the mounting locations your engine already has...then you should be able to use the tube you have. Like you mentioned, the motor essentially becomes the stressed member, and that section of the downtube becomes more or less just for looks.

Jason
 
That's the answer then. I'll fab motor mount plates which extend under the motor.
I really appreciate the suggestions and feedback folks. Thanks.
 
NEW FRAME's ALUMINIUM TUBES CUT / FORMED...
FSCN3723.JPG
 
MEANWHILE....
Whilst waiting to collect the assembled frame from the welders, I've been lucky enough to score a couple of vintage 98cc Villiers Midget engines from two different UK eBay sellers for bargain prices. These will be stashed in my parts pile for future motorized bicycle builds.
First pic shows what was a 'New (other)' listing by the seller. He described this engine as being purchased new by his father for a project which never got off the ground. Turned out I was the only bidder - and scored it for a mere 22 UK pounds. Had to be worth a punt at that price.
Second pic shows a Villiers engine from an Atco mower. Check out the cool shape of that cylinder barrel. Love it. An eBay BUY IT NOW bargain at 25 UK pounds.

villiers midget 98cc.jpg Villiers Atco engine.jpg

I've also purchased the aluminium tube, sheet and filler neck which I'll use to fab the fuel tank for my No. 3 build. Pics to follow soon showing how the tank takes shape.
 
No. 3's ALUMINIUM NEW-BUILD FRAME SECTION BACK FROM WELDERS .... AND THE ALLOY GAS TANK STARTS TO TAKE SHAPE
Got the call from pro welder Paul today advising the aluminium frame section was ready for collection. Paul said the jig I made to hold the frame parts in alignment during assembly made the job super easy. Couldn't be happier with how the frame came out.
While at the welders, I also asked if Paul could tig the baffle inside my under-construction aluminium gas tank using a few tack welds. With luck, I can hopefully proceed with the remainder of the work on the tank this coming weekend. I've formed the tank's two sheet metal panels and these just need trimming to final shape. Also need to decide where to locate the filler neck. Once that's done I'll braze the alloy tank parts together using the same process I described when building DECOLINER's gas tank.
Pics show the frame's alloy and steel front/rear sections bolted together and the under-construction tank temporarily sellotaped between the pair of top tubes to show how this project is shaping up. Wheelbase is a stretched-out 54".

FSCN3746.JPG FSCN3744.JPG RSCN3747.JPG FSCN3742.JPG FSCN3740.JPG FSCN3741.JPG
 
ALUMINIUM GAS TANK COMPLETED...
Finished-up assembling the aluminium gas tank for this project - my second attempt at aluminium 'welding' after debuting this technique on DECOLINER's fuel tank. I again used Durafix brazing rod to attach the filler neck and Alubuild 300 rod to secure the 2 x sheet metal panels to the 4" dia. cylindrical tank shell. All achieved using nothing more than my butane/propane torch. Really pleased how it turned out after clean-up and rounding-off all the sharp edges with a file and some abrasive paper. Pics show the end result - minus the fuel tap. Just need to have 4 x nuts tig welded onto the end panels to accept the tank's securing bolts. I'll have that done when I revisit the welders to have some bracketry and fillets attached to the frame. Really looking forward to making a start on the tank's paint/decals/patina...

FSCN3755.JPG FSCN3757.JPG FSCN3763.JPG FSCN3764.JPG FSCN3765.JPG FSCN3766.JPG
 
Looking good Pete!

Love those spare engines.:cool2:

Hey Jim, Yeah, that pair of 98cc Villiers engines are pretty nifty. Can't believe I scored them so cheaply, especially when one of them actually did turn out to be an unused new motor.
Stashing one engine aside for a forthcoming reverse trike build, on which I plan to utilize the step-thru frame I recently purchased... and when that time comes I'll be chasing you up for another TRM tank.
 
SNOWBOUND...!
Zero progress this week since Tuesday when the 'Beast from the East' snowstorm and temps in the minuses engulfed the UK. Here in remote rural Northumberland we've been stuck indoors ever since and there's no chance of getting out till the plows reach us. The local authority's manpower and plows have had their hands full keeping even main roads like the A1 open - so roads to villages like ours in the boonies are way down the list of priorities. A local farmer has done his best to try and plow out the road here with his tractor - but all that did was pile the cleared and compacted snow 4-5ft high at the single-track roadside - so now it's like a bob sleigh track with nowhere to manouvre when encountering an oncoming vehicle. Besides, I can't even get my car out of my garage thanks to 3ft high drifts and a blocked-off driveway entrance courtesy of banked-up snow from the last plowing attempt a couple of days ago. Absolutely no sign of a thaw. Can't get to the local store to restock food supplies till that happens. Even if we could get to the store it would be a waste of time 'cause there hasn't been any deliveries since Monday - so the shelves are empty.
We're out of bread/milk and other essentials. 'Fridge is now empty and we're now well through the contents of our freezer. Amazing how creative one can get with a box of cream crackers (lol).
No mail delivery since Tues means I'm still waiting for a whole bunch of parts for build No. 3 to show up. Not expecting to get anything anytime soon. I do have other priorities other than bike building right now - but man, being snowbound gets boring real quick. Itching to get building again...
 
How unusual is this for your area? A few flakes stick on the road around here and the media starts screaming about 'snowmageddon'! It sounds like your area's winter infrastructure has been completely overwhelmed :blackeye:. I'm rural as well, and we've never had an event in my lifetime that left us as isolated as it seems you've become.

Best wishes for some relief...good luck!
Jason
 
I can't imagine being stuck in for so long. I hope you can get out of there and get some supplies soon!

A year or two ago we got 3 foot snow storms every week for about a month, but being not far up the coast from Boston, the roads are clear most of the time (but, since our cars take up the driveway, having a snow blower in the garage would require us to shovel the cars out first, kind of negating the point of having one, that was a lot of hand shoveling!).

A Northeaster during three full moon high tide cycles just blew through yesterday (luckily rain, not snow), so I went for a drive while the power was out (only for a few hours). A couple sections of a neighbor's fence came down and a bunch of trees and power lines in the roads, and stuff low-lying on the water got flooded. I can't imagine working in famous seafood places, like Woodman's in Essex as with the frequent flooding, they must have massive mold issues. South of Boston got really hammered, though. Luckily, the guys I had working in Quincy were right off the highway and not on the coast where they had to evacuate people using construction equipment and National Guard military trucks.
 
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