WHY???? would you jump out of a perfectly good airplane - Especially the best utility airplane in the world ??? :) Printing looks great Dave - The best part of it is designing parts like this that are instantly useful.

And YOU TOO Lonnie - That Twotter was barely working up a sweat I bet.... :)

You might be able to tell I'm a fan boy of the -6. I would probably wrench on one for no pay - but they seem to have been OK about paying me to do it... Some Smart guys drew that one up.
I had the pleasure of caring for a couple "classics" We had S/N 8 and 17 in our fleet - Both true workhorses despite their age. Unfortunately both are no longer with us - CCE (S/N 8) crashed on takeoff when the crew decided they would try only removing 4" of snow form one wing prior to attempting a takeoff. The second, SCA (S/N 17) was lost in a Hangar fire..

That triangle shape looks like jbweld... shame about the fin... I'd say you got a good deal for $150 on a limited production engine, its a versatile twin suitable for long narrow nose aircraft, P51 comes to mind.

one of the equipment vendors i specified often rounded up a bunch of engineers and offered to push us out of an airplane. up until that point i was srictly against jumping out of a perfectly good airplane but in that very moment, i got those butterflies in my stomach that i would aways get just before i started to tow up when i was into soaring and i knew i had to do it. i did 2 tandem jumps a couple weeks apart. the first one came with an adrenaline rush that lasted several hours. the adrenaline rush from the second jump only lasted a few minutes. that, and the fact that my brother's girfriend also jumped that second time except that her chute didn't open as cleanly as it should have (they did get it to open though) made me come to the conclusion that jumping out of planes isn't really worth the rush.

Perhaps, but sometimes the pilots did.

One landing was particularly wild, on a compacted snow/ice runway 600 miles north of the AC at a remote radio site. Crosswinds were 55+ knots and I could see the runway flares, which appeared to be coming straight at me, as I gazed in amazement out of the side window. The pilot had the Twotter in a heavy side slip and didn't kick the right rudder pedal quick enough before touchdown. The right wheel ski caught an edge resulting in a violent jerk which rolled the plane over until the right wingtip smacked the runway. The pilot then overcorrected and the same thing happened again, this time the left wing smacked the runway. If we hadn't been buckled in everyone would have swapped seats. That was quite a ride and the pilots apologized as we deboarded. I replied to them, "No problem, good job", in the shakiest voice I've ever uttered.

Now the amazing part. About 30 minutes later I heard the DHC-6 depart. Tough planes!

Why aren't you lot out flying... gorgeous day here, a bit hot though, 98°'s right now.

It's Labor Day weekend, visiting with friends and family. But now that you mention it, flying would be more fun.:D

Well you can Labor another day... time to enjoy yourself :)

Just peaked to 104° here... time to head back to base camp for a cold one... caused enough trouble for the day... water bombing the electric section started to get our of hand, so exit stage left. ;)

Make sure to post those drawings here... I want TBI on my Boxer as well. Should cure the uneven mixture distribution.

We had a pretty big fly-in about 50 clicks from where I live, and Rob M. demoed his Puma with your TBI design, and it absolutely did make an impression, Chris!
Rob has this "rather funky" flying style, which raised some eyebrows for those that were still sceptical about :small gass" and its usefullness... :D

No scepticism here, just don't fly those size models anymore... the boxer is the smallest displacement engine I play with.

Boxer Back together and had a rough drawing done so made some chips - Got the Body roughed out and I think its going to work well - Keeping the venturi on the smaller side as its easier to make bigger than smaller - Even the stock carb is not a big bore.. Hard parts done - Now just fiddling and small parts..
https://cimg3.ibsrv.net/gimg/www.rcu...94af90d362.jpg
https://cimg4.ibsrv.net/gimg/www.rcu...c43836aba3.jpg

Here is an interesting one - I have a soft spot for Enya's... My first plane was pulled by one and I have had some great runners over the years.. Lots in my collection for "nostalgia".

I happened across a "new" one and picked it up - A 40BBTN - Two Needle - When I pulled it out I was surprised to see an air bleed... The TN carb does have two needles but also has an air bleed - Its drilled quite low in the "face" and apparently only works at idle... The low needle is to be used to set the mid range and then the air bleed for the idle.. Can't wait to give this a try to see how it works..

https://cimg8.ibsrv.net/gimg/www.rcu...3b75256c19.jpg
https://cimg9.ibsrv.net/gimg/www.rcu...8ab6ccd290.jpg
https://cimg0.ibsrv.net/gimg/www.rcu...eff39ac48b.jpg

That looks GOOD!!!!

I just drooled on my Keyboard. Are you going to start it with the stock carb or are you going straight to TBI?

It lives
 

Got the 200Ti breathing fire. Just finished the break in runs. Bearings are very smooth but never quieted down, even after 45 min of run time. Oh well, back into the engine I guess. The rear bearing is in a blind bore. I'll use the "heat and slam" method or the "wax and punch" method to drive it out.

The insert worked perfect. Actually wasn't difficult to swage at all. I hope the swaging formed a gas tight seal so it's not relying on the JBweld.

Chris is my Huckleberry on this one. Thanks again!

Looks nice, going to be interesting to see this one completed... don't forget to thermally isolate the TBi body from the crankcase mounting face and screws

Got the Twin TBI mostly finished today.. Everything went well and can't wait to try this one out...

Thanks John for the reminder on heat isolation - I am planning an isolator shim between the body and the case - Wont do anything with the fasteners yet unless there are issues.

Questions:
1) What do you think the fuel needs of the 160 will be in comparison to previous "TBI's". Im considering a 0.3MM jet as starters as the .40 two stroke uses a .2MM and the ST23cc a .4mm.
2) choke ? - The choke does fit and the geometry is right but is it needed . I can do the electronic choke if needed also.
3) I have built replacement stacks (as stock) as the Keleo Exhaust has terrible corners that are flat and the tube it thick aluminum with a small ID. Where should the Pressure tap be located? 2 or just 1?


https://cimg1.ibsrv.net/gimg/www.rcu...dd07b09263.jpg
https://cimg2.ibsrv.net/gimg/www.rcu...9a2c0a30dc.jpg
https://cimg3.ibsrv.net/gimg/www.rcu...1a59bd4f92.jpg
https://cimg4.ibsrv.net/gimg/www.rcu...ca5011b303.jpg
https://cimg5.ibsrv.net/gimg/www.rcu...370c937faf.jpg

Going right to TBI Dave - Im thinking why do the setup twice but I can always throw the stock carb on if I have issues...

So glad this worked out Lonnie - The short tap swage trick is a good one I have to save in the "bag of tricks". - did you have to re-tap after swaging?

Back when I converted my Twin, I noticed to my amazement that this engine is the exeption to the rule.
The cambox remains cool enough for the carb to go without isolating the carb, in fact when I did in summer no real problem but in winter the carb started to freeze up.

The choke is convenient ro have. Sometimes after longer standstill, the gasoline evaporates and the straight oil remains, and the engine is reluctant to pull that viscous oil through.
Engines with muffler pressure are easy to pop through by closing off the exhaust and turning it over, the pressure build up in the fuel tank will push fuel to the carb.
But with the boxer, closing off two exhausts is a bit of a hassle, and putting a finger over the intake, the intake is at an inconvenient location for that.

It won't hurt being there if you don't need it, but it's a nuisance if you turn out to need it and it isn't there.

I am above all wildly curious if this TBI will cure the uneven fuel distribution at part throttle.

Pressure tap: My twin has both exhausts tapped, connected with a T-fitting (NOT an Y-shaped one but really a T-shape). That makes the crud basically shoot back and forth between the two exhausts leaving a much cleaner pressure supply to the tank. I still use a craptrap, but I barely ever need to empty it, significantly less than the singles or the radial.
A single tap probably works just as well, and I have never done any measurements WRT what results in the highest tank pressure, but the reduction in crud (A "reduced craptrap load", how's that for a technical parameter? :D ) is always a nice thing.

On Saito FG gassers there is no choke and no muffler pressure tap. To make things worse the vacuum signal from the intake is too weak to make the pump effecient at start up with a dry-ish carb. The only answer to getting fuel to the dry carb is to apply pressure to the tank through the tank vent. For my cowled FG engines I have to bring a large syringe to the field for the first start of the day.

Location of the pressure tap on a constant diameter exhaust header is important. Velocity drops along the length of the tube, therefore pressure rises. The pressure tap should be located near the end of the exhaust tube for max pressure.

Chris, what? No dual carbs and dual controllers on that twin? :D

1.my math says .25. remember, this is like two .13cc engines with intakes at differing times so you need a carb for a 13cc engine.

2. Choke is not needed. Place finger over exhaust pipe with pressure tap and flip to prime. In fact, the choke on mine got them bed rather than cut the cowl.

3. Not sure on this one. Mine is tapped right after the bend but I have stock pipes.
4. Make extras (if you want). Bert and I will pay you.

...also, no isolator on either my ft120 or the ft1.60.

If the Boxer TBI works out I will make a few more for "Group Testing" and will sketch up a good set of drawings also for others to build.. Is the 1.20 size carb identical mounting ?

Bert - When I get to testing what am I looking for in regards to the Uneven distribution at midrange?

Hope to get a shop clean up done - and move on to the Ignition install and a "Mount Plate" as I didn't get one with this engine.

Mounting is the same for the 120 as the 160 but I would assume if the .25 orifice works for the 160, you would want an orifice closer to .21-.22 for the 120