Sandman Norway

Hmm, might be a combination of things: To mutch oil, old plugs to ritch..

Anyway starting is easy, no problem getting it to fire.. I have just removed it from its test stand, and are about to adjust valves..
My german is not all that good :-( From the instruction, it`s seams that the valves should have a 0.10-0.15mm gap.. Is this correct, as I see later that 0.05 is written..
And a 0.05 feeler blade was delivered with the engine.. So, what should I adjust them too..?

Any insight would be apriciated...

Mfg Sandman

the Gnome

Hello Sandman, yes, 0,05mm to 0,10mm is correct, I adjust to a point so that the 0,05 gauge slips through freely and the 0,1 gauge sticks a little.

Did You loose the cylinders at idle or full throttle? If Your engine is new, Seidel sais 10% oil is ok for the first hour. Is the exhaust gas wet, i.e. can You see fuel spray coming out of the exhaust stacks?, then it's running too rich.

gnome

Holm und Rippenbruch

the Gnome

Oh, something else, be cautious when adjusting the valves for the first time, it is not very probable, but on my ST 710 the valve timing (cam ring gear) was adjusted too early, so that the inlet valves were touching the pistons when the gap was less than 0,15mm. At overlap TDC it is correct when both valves open for the same ammount.

gnome

Holm und Rippenbruch

Sandman Norway

Gnome... Yes I see a lot of oilspray from the pipes.. Messy little engine, but love it.. :-)

I have adjusted the valves like you said, and did this time run it without the colector ring. All cylinders fired nicely. I will tomorrow run it a little more lean,
it has now seen 4L of 10% oil fuel, and I have a fresh 5L with 6 % oil.. To me it seams that it ran better on stright pipes, than with the colector ring..

I*m a bit reluctant to lean it out, as I "only" have a 22x10 Menz prop at hand, my last run was a little above 6K RPM, so I guess I should have a 23x10/24x10 or a 22x10 tri.blade..
Dont want to over-rev this little beuty...:-)

Is there any benefit from using nitro on this engine at all..? Regarding my initial problem with "dropping" cylinder..?

Anyway, the cylinders that was "dead", I beleve that they fired up at full throttle, but not quite shure as I used the col.ring.. Mutch more easy to tell with straight pipes..

All do some more testing tomorrow, and post my findings...

Mfg Sandman

the Gnome

Sandman, on my ST710 or ST540 the only difference with nitro (10%) was an about 300rpm higher idle (without nitro 800rpm, with nitro 1100rpm), no gain in max. rpm. My manual sais, the 770 or 710 should not rev much above 6k on the ground, so Your prop selection will probably be ok. Try if You can get the dead cylinders again by switching on the plug heating at full throttle for some seconds, if this works, it really may be to rich.

And You are right, the 770 really is a fine engine, I love it too, this winter it will make a combo with a Savex Aero A102.

gnome

Holm und Rippenbruch

Sandman Norway

Gnome...

Thanks for good info..

When/if I get it to run perfectly it will be the power plant in my Sist FW-190A8 (1:5 scale). I know its on the low side regarding power,
but should work out ok for scale flight on the F-190.. If it turns out to be a little temperemental, I`ll put it on a bibe :-)

I*ll be back with more info later today, after I have switched to 6% oil...

Mfg Sandman

chasrb

I have had a similar problem with my ST710 where the bottom two cyl do not seem to light, even though I have the igniter on. I checked the glow plugs and they work. So my next step is to put two non-microsens glow starters on the cyl that do not light and see if that gets them going.

I am using the 7% oil. I have run about 1 US gal through it now, I probably should drop it down. As a note I noticed that when I run the engine (with collector on) I get a lot of black exhaust residue. Could be from the two non running cyl.

Sandman Norway

Hi Chasman..

My problem was that the two lower cylinder ALWAYS fired, but had trouble with the upper 3..
I did allso see black resedue with the collector ring, I beleve this comes from corrosion inside the
ring.. It certenly do not come from the engine..

I think that I will build a rigg to see if I have constant glow on all plugs using the Microsense unit. It may allso be that there is
a electric resistanse difference from cylinder to cylinder.. Not shure how the Mircosense would react to different Ohms values..
Maybe a better "grounding would help..

Mfg Sandman

the Gnome

Chas and Sandman and others, as I plan to use a microsens glow driver on my ST 710 too, Your descriptions made me thinking over the problem in detail. In fact, the microsens kind of wiring the plugs, always four in parallel in one line and three in parallel with the shunt in the other line can cause some trouble. The ampere figure in both, the positive and negative line, are the same, but the current flow in each line is ditributed differently. As in one of the lines there is the shunt resistor instead of a glow plug, the resistance of this line depends not as much on the amps (or plug heat) as in the other line. So these three (see above! Chas had trouble withe three cylinders!) plugs will lite not as much as the others, because a higher ammount of current flows through the shunt resistor compared to the plug current of the three plugs in parrallel.
If the plug current is near the figure,, that is enough to produce a correct ignition, may be that the small ammount of less plug current in those three plugs causes the cylinders to stall.

I hope I could explain tis phenomenon good enough, my english is not so good. On my test stand I use 8 2000mAh NC Cells in parallel wo lite the plugs, so they all get the same voltage. I think I will test the microsens during further runs with the ST710, I really want to know if I can produce the same problem.

In the MONOCOUPÉ with the TECHNOPOWER 7A I use an old german HÖLZL glow driver, that provides a seperate circuit for each plug that can be set to individual current, and I did not have any problem alike.

What do You think?

gnome

Holm und Rippenbruch

Cybertom

Robart R780 Radial Engine for sale on eBay

[link=http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260176653223&ssPageName=ADME:B:SS:US:1123]Robart R780 eBay[/link]

I contacted the seller about this engine and told him which club I'm with in the area and that I have the same engine. After all I'm a only a stones throw away from Akron and I have never heard of anyone else owning a R780 in the area other than me. At this point he is only willing to respond to questions about the engine.[sm=50_50.gif]

stevesak

My Feedback: (27)

Yup. He send me photos of it last week.

The seller; (Richard C.) listed a 9 cyl Techopower B last week and has two 3 cylinder TPs for sale right now on eBay.

I asked him about others early last week and he sent me photos of 17 other (yes, seventeen) Technopowers that he is selling.

I asked Marc Linville (Current TP owner) about him and he says that he has the same last name as the gent who did most of the major Machining for Elmer (Last TP owner). The Machinist's name was Ron C. and received much (if not most) of his payment in finished product.

When I asked Richard C. if he was also known as "Ron" he didn't offer up any other info and wasn't receptive to normal communication. He just said "No.. my name is Richard".

He send me photos of 17 different Technopowers of every size imaginable and expressed a willingess to sell them off-site, but when I asked him about prices, he just balked.

It's a little strange. He may be Ron C.'s son? Brother? Perhaps from Ron's estate? Living estate? I mean, how many guys with the same last name as the principle machinist would be running around with 17 or 18 Technopowers?

Marc L. said that Ron C. was a large collector of other engnes as well, and that could explain the Robart... and maybe others to come, too.

I just wish that the guy was a little easier to talk to...

Like I said... Strange. But probably legitimate.

--->Steve

stevesak

My Feedback: (27)

and the rest.... They are all going up for sale, too. I wish I had an extra thirty of forty thousand!

Kmot

My Feedback: (24)

Wow, that's a nice collection. [X(]

Cybertom

Kmot,

You can tell that's an older R780. The engine specialist at Robart (Larry) said that they had issues with the studs that hold down the cylinders on the older engines. They switched to S.H.C.S which resolved the problems. This engine will also need the pinned crankshaft update. The existing crankshaft can be modified but it will need to be sent to Robart for the update. I'm guessing around $800 to $1,000 dollars for all of the shop time parts and a 2-hour bench top break-in. After all of that I would be willing to bolt it into a airplane.

kochj

THere is a video on Rcunivers that thas the saito 5-cyl on a September fury .
It looks to be a KMP model...
The weight of this engine is 5-pounds! I am surprised it flies as good as it does in the videos. Seems to have no problems at all..
Can anyoneverify this?
Justin
http://www.rcuvideos.com/item/VN8KVPCXXB56T28Y
that is the link...
Thanks

TURBINATOR

Good luck putting the cowl on!

Aluminum Overcast

All KMP models are very tail Heavy. I have the long nose Spitfire which I'm currently building and even on that plane guys are adding 2 lb. to the nose to get it to balance. I'm using an articulating ground adjustable pitch scale outline 4 blade prop (center hub is heavy) on mine so I think I won't need any useless weight. There is a great thread going here on RCU about this plane. KMP Responds by saying their planes are very scale in outline and they have not extended the nose of any of their planes to help balance them because the scale accuracy would be counter to their scale philosophy. Still the planes fly well with this weight regardless. The CMP 50 CC Zero next on my list will also be tail heavy for the same reasons, that's why I'm mounting the ASP 400R in it. I can use the nose weight and the sound!

the Gnome

seems as if he has cut the front of the cowl and used the rest to cover the engine mount, to hell with scale appearance (sometimes), why hide the fine radial?

gnome

Holm und Rippenbruch

Aluminum Overcast

True, It's a beautiful engine, but in my opinion, on that plane, it needs a cowl unless he's making adjustments or it's just a test mule. That's the great thing about this hobby, so many different elements to focus on. What's important to me isn't necessarily important to anyone else

Kmot

My Feedback: (24)

This I must see! I have wondered if the 400R would work on this model.

Ram-bro

My Feedback: (101)

Kmot, me and you both have wondered. How is your 400 doing anyway?

Aluminum Overcast

Here you go guys...... the first few are the prop detail on the KMP Spit I'm currently working on and the others the 400R detail in the cowl of the CMP Zero...Just barely fits, actually, it rubs the cowl. I'll need to make the cowl a 2 piece and add just a few cm to each side for clearance. Like the Spit, the Zero will have a scale shape (3 blade) variable pitch flying prop.

http://gallery.mac.com/geod1#100066

the Gnome

Aluminum Overcast, can You tell me where I can get such a scale locking prop? It's really cool!! Is the engine underneath the Spit cowling a RCV 120SP? What is Your experiance with the engine, I rally hate mine!!

gnome

Holm und Rippenbruch

Ram-bro

My Feedback: (101)

so what will the Zero weigh when done? What size prop are you going with?

Aluminum Overcast

Gnome,

Solo Props : http://www.soloprops.com/

The owner is a great guy and provides excellent service. He can make just about any size and shape prop you need. Best of all it's for Flying too not just show!

Regarding the Spit:

Yes, the engine is indeed an RCV 120 SP just out of the break in and just mounted for position so I can make the exhaust header and scale stacks. With that Solo 18 inch prop and quite a bit of pitch dialed in (around 10 for the pitch) I'm getting 4,800 RPM with 10% Omega. I could get more but know the prop will unload in flight and as such, don't want to exceed the rev limit (5,500) as this is 2:1 gear reduction engine as you know. So far, it has proven to be a very reliable engine and should be plenty for this aircraft as the proto flew with a RCV 90....not an SP series but the same mechanical theory involved.

Personally, I like the sound it makes, it's very different as the whining gears give the engine a supercharged sound, particularly front the prop and side opposite the exhaust, The rest of the noise is pure four stroke.

I also have an RCV 120SP of earlier vintage and they have made some changes to them IS yours fairly new? I don't have bench test data as it's planned to go into a TF P40 I'm also working on. Tis plane is on the shelf till the Spit and Zero Are flying.