How to Run Saito 62 and 72 in reverse (clockwise)

[Chris Wilson]

Don't think the pushrods or tubes are long enough to criss-cross, plus tappet angle.

Yeah, agreed. Really impractical but how else would you contemplate this?

[Bob Reeves]

Little update on my reverse 62.. Put the engine back in the SomethinXtra with my modified RC carb and it runs just fine with the JFX 13-6. It was good enough to win Advanced at our contest this weekend (in 15 mph wind) even with a not so well trimmed airframe. So why doesn't it work in the Latency?

I think the intake configuration is the key as that is the only real difference between the two airplanes. When I built the Latency I was flying a Score with a Dixon intake and the nylon screw running down the throat. It was working well and was before I started modifying RC carbs. This is the same intake system I used when I built the Latency thinking it should work just fine and it has with a stock 62 turning a 3 blade carbon prop at 8400.

The Dixon intake is a conventional spray bar using a PA needle assy with the choke above the spray bar. The modified RC carb is a spigot with the choke located right at the spigot. I believe the spigot is not only better at atomizing the fuel but because the choke is at the spigot the smallest area in the intake is right where the fuel is fed into the air stream. The result being more consistant fuel draw and the ability to do finer adjustments on the choke area.

So what's the next step.. I'm thinking I need to build another Latency with a wider fuselage. The present Latency was built using a Legacy fuselage and the RC carb intake ends up with the needle at the same location as the fuselage side. Guess I could add a cheek cowl but that would look kinda silly on a Jet style airplane.

One other thought is to modify a 56 for reverse rotation and run the same prop as the 62, just maybe the combination will allow me to open up the choke enough to get out of the critical position with the choke screw I found with the 62. In the mean time, I have a great airplane running a stock 62 and a windy weather airplane with the reverse 62. Back to the drawing board......

[Jim Kraft]

Hey Bob; I just checked the wind in Tulsa yesterday, and it was gusting to 23. You did good, and I thought your motor run was very steady. That old four stroke sure sounds sweet.

[Bob Reeves]

Thank you Jim, have allot of respect for you and your opinion.

Just tickled me that the Saito was able to out fly both electric entries. I've never seen Paul Walker's or Bobby Hunt's electrics fly but have seen some pretty good electrics at Brodaks and so far I'm not real impressed.. Maybe I can get away with saying that in the 4 stroke section, doubt many electric guys visit here 

What really impressed me and something I wasn't sure about was how much wind up I would get when the wind was blowing, as you saw it did just fine. I remember when I first started messing with 4 strokes, Joe Gilbert and I were flying the Score with the Saito 56 set up like most at the time in a 10-15 MPH breeze. That thing was doing at least 90 at the bottom of the verticals and I came real close to abandoning the whole 4 stroke idea, sure glad I didn't.

[Douglas Ames]

I'm curious Bob, what's the weight difference between the SomthinXtra and the Latency? Which do you think has more drag? 

[Bob Reeves]

Weight is about the same, at first I was thinking the Latency has less drag but after thinking about it I would guess they are close. The Latency is a trike and the SXtra has a wider fuselage, wings are about the same thickness and airfoil. This is what lead me to the main difference being the intake configuration..

[proparc]

Maybe I can get away with saying that in the 4 stroke section, doubt many electric guys visit here 

Your the moderator of this forum, you can say whatever you want.

[Bob Reeves]

Your the moderator of this forum, you can say whatever you want.

Not quite, Randy Smith is the moderator, I'm a nobody that hapens to like 4 strokes.

[proparc]

Not quite, Randy Smith is the moderator, I'm a nobody that hapens to like 4 strokes.

Really, I thought you were the one that started the 4 stroke forum? This doesn't change anything, your still a nobody,(don't want you to get a swell head).

[Martin Quartim]

Bob,

Good job winning last weekend contest!  Flying the pattern at 23mph is really tough.

Thought you might want  to know that Himodel can special order 3 Blade Pusher props also.

My reverse camgears got lost in the mail and now they are sold out. I gave the idea but seems I will be the last one to use it   

Take care,

Martin

[Bob Reeves]

<snip>
My reverse camgears got lost in the mail and now they are sold out. I gave the idea but seems I will be the last one to use it   

Take care,

Martin

Ya, I wanted to order another one for my other 62, now they are saying they won't have any till November, guess that isn't too far away now that we are almost into October. I need to get back out to the shop and try the one I bought for the 56 and see if it's going to work..

Still up in the air on props, the 13-6 JFX works well with my spigot carb but not sure if I can retrofit the Latency to a spigot. Hate the idea of spending $ on props that may or may not work. I've already given 4 of the 6 JFX props I bought away to another club member that runs electrics as they didn't work for me.

[proparc]

Still up in the air on props, the 13-6 JFX works well with my spigot carb but not sure if I can retrofit the Latency to a spigot.

Anybody use any of these for the 4 bangers. I am goings to get me some, and see what the hell is going on!!

[Martin Quartim]

more 3 blade e 2 blade pusher props that could work witht the otiaS:

http://www.shop-online.jp/mnti/index.php?body=list&category_id=124526&PHPSESSID=f22155bcf2403713ce751e4a24db9ffc



Martin

[Dennis Adamisin]

.... doubt many electric guys visit here 

Some us us just lurk, admittedly not very often.  I AM tickled to hear of your success and hope you get to continue the experiments on other engines & airplanes as the parts come in.  Of course I'm looking forward to seeing you and the reversed Saito's at Brodak next summer.

What I do not recall seeing was your assessment of pusher versus tractor, in a nutshell is it proving out for you?

[Bob Reeves]

<snip>
What I do not recall seeing was your assessment of pusher versus tractor, in a nutshell is it proving out for you?

In one word Yes! Where I really notice the difference is in the verticals and overhead 8. It's subtle but enough to make it worth the effort.

[Bob Reeves]

Looks like Horizon has the cam gears's back in stock, need to get one ordered for my other 62.

http://www.horizonhobby.com/products/cam-gear-left-dd-SAI182TD34

[Mike Callas]

Looks like Horizon has the cam gears's back in stock, need to get one ordered for my other 62.

http://www.horizonhobby.com/products/cam-gear-left-dd-SAI182TD34

I got mine ordered yesterday! This Otais 56 is going into an SV-11.

[Bob Reeves]

As promised here are a couple photos showing proper and improper crank position when installing a reverse cam in a Saito. Engine on right is a stock 56 with the crank positioned just as the intake valve starts to open. If you observe the rockers you will see the exhaust valve fully close just as the intake starts to open. This is the positron the cam needs to be in when the crank is in the position shown (more or less) in the first photo. More or less because I moved the crank slightly when I sat it on the bench for the photo.

What I discovered is Saito conveniently machined a pointer into the case and this little peak just happens to be at the exact location of the crank pin when the engine is timed properly. If you were to draw a line from the point of the peak through the center of the crank pin to the center of the crank hole this is where the intake valve just starts to open. Compair the stock 56 on the right to the reverse 56 on the left with the understanding the one on the left had the crank rotated very slightly when it was sat back on the bench.

Second photo is showing where the crank ends up if it's one tooth off. This is the only way I see to get the timing set correctly as the timing marks on the cam gear are not located properly for this application. Trial and error is the only way I have been able to get everything in the proper position. I did remove the gear housing after I had one set properly just to see if a timing mark was located where it could be referenced but no luck as the punch mark is up in the cam housing when everything is right.

[Bob Reeves]

A little update to the above post. After you have the engine together and before you install the back plate and valve covers make sure you check to see if at TDC both valves look like they are open the exact same amount. I am pretty sure I just put a 56 together with the cam one tooth off. When I put it on the test stand I could only get 8500 RPM out of it with a JFX 13-6. The stock 56 I tested when I did the 62 would turn the same prop at 8900. I have taken it back apart and moved the gear one tooth, it now looks like the valves are both open the same at TDC. Here in just a little bit I'm going to put it back on the test stand and see if I get my 400 RPM back.

I'll post my findings later today and thank you Jim Kraft for proding me in the right direction...

Yep, had it one tooth off.. Just returned from the shop.. It now turns the JFX at 8960 like it is supose to. Verry important to double check the valves at TDC to see if both valves look like they are open the exact same amount. thanks to Jim Kraft for this little tip.

Now that I have a good reverse rotating 56, next step is to swap out the 62 in my Latency for the 56. I'm really hoping the 56 will work with the Dixon intake. I'm counting on the 56 not having the balls the 62 has and I can run it with the intake more open than I was able to when I tried the reverse 62. Think I posted my trials and failure with the Latency on the first page of this thread.

[Jim Kraft]

Sounds great Bob. I think you pretty much had it figured out from the beginning. Sometimes though, two heads are better than one. I do think the 56 is one of the nicest handling and running of all the fours strokes I have run.

I am going to have to put a Super Tigre 46 on my Magician now. LOL

[Bob Reeves]

Flew the Latency with the reverse 56 at Brodaks. First item I discovered was that a reverse rotating prop will do just as much damage to fingers as a normal rotating prop. Pulled a stupid move on Sunday before the contest started which almost messed up my whole trip. I didn't fly nearly as many events as I had planed as my head was messed up but forced myself to fly the Latency in advanced PA.

I have to give complete credit to the engine and airplane to pull off a 3rd place because the pilot sure wasn't doing his job. After the prop strike I wasn't worth a hoot and wasn't sure I would/could even fly it. On Monday before everything started I asked Joe Gilbert if he would fly it just to be sure I had it set right for the new prop I had to use to replace the one I broke on my fingers. We set the needle and he called it good..

On Friday without flying all week I just fueled and flew without touching anything and it ran perfect. That was the flight that earned the placing, my second flight the next day was really bad. It was all my doing as just like the previous day the engine ran perfect without touching the needle. The airplane went exactly where I told it to go which wasn't quite what a pattern is suppose to look like.

I'm very happy with the reverse 56 in the Latency it has worked out well. The 62 has just enough added power to make the combination of the Dixon intake and JFX prop unusable but moving to the 56 and selecting the JFX prop with a true 6 pitch on both blades solved the problem.

Looks like I will be building another Latency that I can use a modified RC carb on a 62 in and be moving up to Expert  

[Martin Quartim]

Bob,

To get a 3rd Place at Brodaks it means the pilot was doing a heck of a good job. Congratulations!

Martin

[Chris Wilson]

Your logic is flawed. A reverse 2-stroke crank would simply have the intake port machined on the "other side" of the crank pin for reverse running...on a single cyl. engine.

But the intake of the transfer port is still 'going against the tide.'  That is the point.