11/127 manned flight engine.

[racket]

Hi Mark

Thanks for the offer , I need 90mm dia by ~110mm long .

Cheers
John

[pitciblackscotland]

Hi John,

I have some 6061 Aluminum solid round stock it's 130mm dia. Have some smaller dia round stock as well but don't know if it's 6061

Cheers,
Mark

[racket]

Hi Mark

130 mm , heh heh , a tad wasteful cutting that down to size , I guess I'd better make sure I'm using something pretty tough to take the stresses .

Cheers
John

[racket]

Hi Guys

Its been a bit quiet on the Site lately so I'll Post a coupla boring pics just to have some "activity"

The shaft tunnel needs to be ~10 mm larger in diameter than the 12/118 engine's so I need to increase the inner diameter of the flametube to compensate and allow enough airflow to the FTs inner wall .

Thankfully the 12/118 flametube was a bit "generous" with its cross sectional area at ~3.5 inducer areas , so even with the larger flow from this engine I can still get my "standard" 3 inducer areas even with the increase in flametubes ID

12/118 engine flametube front wall die opened out from 134mm ID and is now 145mm ID with 263 mm OD






Nice to have the smell of vapourised cutting oil pervading my workshop once again , its been a while

Cheers
John

[turboron]

John, what is the swing of your lathe?

Thanks, Ron

[wannabebuilderuk]

May 31, 2021 7:00:39 GMT -5 turboron said:

John, what is the swing of your lathe?

Thanks, Ron

Just big enough 😁

[turboron]

John, I remember that you had to grind away some of the bed.

Thanks, Ron

[racket]

Hi Ron

Its a 14 inch swing lathe, but I did have to grind the bed when machining the SKULD666 comp housing postlmg.cc/cK6B8pDY postimg.cc/N9hGJCyD

Cheers
John

[slittlewing]

Nice machining work John! Will you make a female aswell, to press the flat sheet between? Or just “peen” it over?

Cheers
Scott

[racket]

Hi Scott

Without access to a press , I just get the oxy onto the 2mm sheet, and with a suitably sized/shaped "hammer" , give it a flogging to roll the edge , a bit one side first then a bit 180 degrees away , then 90 and 180 again so that its held in place and can't wander as I roll over the rest , I clamp a 6mm thick steel ring over the sheet to keep it flat , a press would be much better and a lot easier .

With thinner sheeting I can get away without the oxy , its good enough for a prototype, the flametube is only a tin can with lotsa holes in it, no need to be too pedantic :-)

Cheers
John

[slittlewing]

Fair enough, sounds like you have a good technique nailed. There is a lot to be said for coming up with “workarounds” that enable us to make things with the tools we have available!! It’s a must for this hobby.

As you say, 2mm sounds pretty thick though, 1.2 might make your life easier!!

Cheers
Scott

[racket]

Hi Scott

Yeh , 1.2 mm is what I normally use for the side walls , I might even use it for the front and back walls this time as theres no evap tubes that need mounting in it and I'll be using the same fueling arrangement as Andy used in the kart engine , also I want to keep weight down as much as possible .

Workarounds are a way of life for me, not much engineering done around here, its getting harder to build engines .

Cheers
John

[racket]

Hi Guys

Found a piece of 1.2mm stainless sheet amongst by "stockpile" of crap , so decided to start making a flametube front wall .

I needed to mount the stainless on my faceplate and cut out the inner disc , then with a large V belt pully holding the sheet flat against the faceplate I split off the ring .

How I envy you guys who have laser cutting available .

Removing the inner 130mm disc isn't too hard , but the 280 mm cut gets a tad awkward as the lathes slowest speed is too high for stainless at that diameter , but slow and steady small cuts gets it done.



Tomorrow I'll markout the ~200 holes that need drilling in it after I roll over the edges

Cheers
John

[slittlewing]

Nice work John, even if it was painstaking!!

If there is nowhere in a nearby city that will laser and send to you, more than happy to get things done here and post to you in future 

Cheers

Scott

[enginewhisperer]

There are many laser shops, but I think John's allergic to CNC

John - I also have a CNC plasma cutter which makes short work of this type of thing (but leaves it messy enough so there's some manual work left to do