Dave Larkin <  > contributed:

On the small 'Millses' there may be a real problem. But first, which engine is Bob talking about? VA makes a Mills 0.75cc replica in two sizes: 0.25cc and 0.4cc. (This becomes 0.015 cu in and 0.024 cu in.) They also make a scaled-down Mills 1.3cc @ 0.5cc or 0.03 cu in.

I don't know who makes a 0.018 cu in Mills. But VA does make a Kalper of 0.3cc/0.018 cu in. If the motor Bob's having trouble with is the Kalper, there can be an easy explanation. The Kalper is a delight to handle, but you can set yourself up for trouble with one. I'm going through this with one customer right now.

The Kalper is a screw-together engine, as many of the early engines were. As you break the engine in, you have to keep tightening things up until the engine has been through enough heat/cool cycles and everything eventually stabilizes and stays together.

The two problem areas are the front housing (with its LH thread), which can come loose -- and the cylinder assembly. The front housing should be self-evident (there's no need to use brute force, but cleaning and applying Blue Loctite may help) -- but I had one engine returned to me with cylinder problems.

If you look at the layout of the engine you can see that there are two ports for the exhaust, one on either side of the cylinder. These are symmetrical. There is a transfer port in the front of the cylinder between the two exhaust ports. The fourth port is lower, and in the case of the VA MK II Kalpers, is below the RH exhaust port.

If you simply screw the liner down until it bottoms and then align the exhaust ports, without keeping track of the two other ports, you may end up with a liner that is in place 180 degrees out of position.

To correct the alignment, hold the cylinder in place by inserting a toothpick or a piece of plastic (not metal) in the exhausts, and tighten the head.

Another possible source of trouble is the threaded hollow brass connector/manifold that connects the tank and the crankcase. If abused by the application of lateral pressure, this breaks or cracks easily and must be replaced -- a customer broke 2 of those.

To fix the problem, place a new manifold in the tank and tighten it by hand until it bottoms. Fit the locknut and insert the assembly into the crankcase. Do not turn until it bottoms, but leave about a 1/16" gap. Then tighten the lock nut against the crankcase.

So in the case of the Kalper the problems are nothing at all to do with diesels, but are just a lack of understanding about how an old engine was designed and constructed. A 6 X 3 wood prop works well on a Kalper. To be on the safe side I'm updating the Kalper instructions to emphasize all these points.

The Mills may be different. As I say, VA produced these in two sizes. They are pretty good, but the bigger one runs better. However, we decided to try an R/C carb, and asked for a prototype carb to be made for us to try. VA responded by doing a production run of carbs, which did not work too well (as we half-expected) as the engine has sub- piston induction. So, being slow learners, we asked VA to do a prototype engine without sub-piston induction. As you have probably guessed, he did a production run.

At the same time, he incorporated another unknown modification at the behest of the UK agent, Dave Banks. Did VA test them before shipping? Apparently not. I had an order in, which inadvertently got doubled, leaving me with an ample supply of attractive paperweights.

After much frustration I sent them back to VA. They were returned, supposedly fixed by the addition of a spacer which changed the timing. I tried one and it seemed to be OK. But I wasn't in the mood to tackle any more tiny Mills replicas after all this nonsense, so I put them aside and concentrated on the Bambi 0.009 cu in and the FROG 50 @ 0.015 cu in, which were relatively trouble-free.

Then VA came out with a Mills 1.3 @0.03 cu in which hasn't given any trouble yet and is a delight.

When I got back to the earlier Millses I didn't have any luck. They are going to have to go back to the factory yet again; hopefully for completely new pistons and cylinders that work; either that, or to be replaced with something else.

If you bought an engine from Neville Palmer in New York or from me, there shouldn't be any functional problems, as we test them all before shipping. But occasionally some slip in via Tomas Mejlik in the Czech Republic or from the UK, and I can't vouch for those. Woody Bartelt of Aero Electric has had some engines from Tomas, too.

By the way, Aerodyne fuel is excellent quality but it is best for high performance diesels. It only has 20% oil. Add another 5% (castor) oil if you use it in a plain bearing engine or a vintage replica.

As I'm sure others will point out, Walter Legan's problem is spin recovery technique. If you are lucky, neutralizing the controls may work, but it's not the correct procedure. This is: apply full opposite rudder, then increase down elevator until the spin stops.

Release the rudder control as rotation stops, then gradually allow the elevator to return to neutral.

Dave Larkin

Larry Marshall <  > wrote:

Jim Branaum was wondering if the 50" Easy Built Spitfire could be converted into a .25-powered R/C model.

Before confusion breaks out, EB sells a 50" Spitfire for electric power. It is in no way similar to their FF rubber kits, and the airframe would weigh much more than Sam Brauer's 8-ounce P-40.

Cheers --- Larry

Dereck Woodward <  > declaims:

In reply to John, the fan of small airplanes for many years, with a passion for high-performance .25-powered, 3-foot-span airplanes:

When I flew glow, I seldom flew much other than 25's. Nothing quite as ferocious as yours, but not much passed mine. You can put a 36" - 40" model behind a modern 25 well under 48 ounces and it will move. One of my hottest was "Bubbles", the 40" tailless RCM published around '94. This started life as a Low Aspect Ratio wing out of a conventional model I'd designed earlier.

I eventually built three, and little could live with them. Eventually, Bubbles #3 got an OS 25 SF ABC and that really left everyone in the weeds.

I never bothered with pipes - most of mine had oversized mufflers grafted onto them as I can't stand the whine of a two stroke engine -- a funny admission for an R/C flier, I agree.

One of my best ones was a now long-defunct cottage industry 48" span aerobatic kit. I once flew an FAI aerobatic comp with that one -- might be the only occasion on which an OS25FP has competed in such lofty regions. Got around the pattern in three rounds too -- albeit with somewhat smaller sized maneuvres compared to the real pattern machinery.

Your Gee Bee sounds worth trying - plenty of power from a responsive engine and keep the model real light. That size engine is really great -- you can get performance to match the 46 stuff, plus everything on the model is rock bottom cheap. I always used standard servos in my 25 designs -- often wonder how they would improve for losing ounces more on servo size now -- and 4 or 6 ounces of fuel would give ten minutes or better of real sizzling performance.

Used to run the OS 25FP on 5% or even straight fuel, and their handling was impeccable - nearly as easy to start as my electric models.

One engine I really loved was the OS 26 Surpass. Even had mine in a couple of aerobatic models, a real gem of an engine.

Maybe my love of 25s was due to learning on one - that showed me all that size did differently to 40's was use less fuel. Commercial hype s ells 46s -- if you ran a hobby shop, wouldn't you rather sell something that needs 12 ounces per flight rather than 4?

Regards, Dereck

Fred Reese <  > contributed:

Bob Slater: I am currently running the Thunder Tiger GP25 in a new slow fly design with 800 sq. in. The engine is great. Lots of power, good low end transition and idle. I am using a Master Airscrew 10 x 4 prop. Performance is from docile to wild. The aircraft weighs about 3 1/4 pounds. I like the engine.

I have been reading the biplane wing conversations with interest. My Golden Oldie was mentioned, and it has the positive angle in the top wing and zero in the bottom. I have used this combination for years and it produces a very docile model. At stall, the model just noses down a little and continues to fly forward. It would work on a free flight just the same. I used it on the three-channel configurations of the Hopper and Doppeldekker biplanes published in RCM many years ago. I also used it on the Sopwith Triplane using three Ace RC mini foam wings (constant chord).

As I remember, on the Sopwith I used zero on the bottom wing, plus one for the center wing and plus 2 or 3 on the top wing. Power was an OS 15 and performance was fun but mild. The stall was the best part. The Sopwith would kinda come to a stop, drop the nose a little, and then just continue on. Kind of a non-event.

However, if using ailerons, there must be ailerons on the zero wing. This goes for any of the configurations. If the first wing to stall has the only ailerons, there goes the control. Many years ago I built a 42" Beech Staggerwing with symmetrical airfoils and KB 40 engine. It had Goldberg retracts and was a blast to fly. Unfortunately, I only had ailerons on the lower (forward) wing and it had a little positive angle too. All was fine until time to land.

Just before touchdown the ailerons went away and my landings were pretty bad. Four ailerons would have solved the problem. This explains the reasoning for the ailerons on the two Hawker airplanes that JW was talking about.

Having tried both single sets of ailerons and double (both wings), I much prefer to have ailerons on both wings of a biplane. The Golden Oldie has four ailerons and the rolls are very nice. With only two ailerons in the bottom wing, the rolls are awkward, more of a barrel roll. I also mix in a little rudder with the ailerons.

The top wing positive system is best for slower biplanes. For faster, aerobatic types zero-zero or even having a little negative in the top wing is better. Adjust the angle of the top wing for knife edge to reduce the amount of elevator needed. Four ailerons are used of course.

Fred Reese

Jason <  > wonders:

Information about fixing nicad packs always confuses me. I've taken apart a pack and replaced a bad cell. Now, I discharged each cell to ..9 V, but by the time I get to discharge the last cell, the first one had come up to over 1.1v. Each cell has a slightly different value.

Does this mean I can't place them together again? How do you get all the cells to stay at .9 V before reassembling them?

Thanks, Jason

Randy Randolph <  > hints:

The Diesel Doctor, Eric Clutton, is offering a ten square foot sample of his "Millennium Film" for $4 postpaid. It is a very light-weight heat-shrinkable film with heat actuated glue on the back side. When heated it becomes fully transparent.

The glue side is paintable with Acrylic type paint if you want a more opaque film. I have tried some, and it works as easily as Oracover clear, at about half the weight.

Randy

Tom Beveridge <  > inquires:

Can any of you radio experts out there help me? I have a HiTec Prism 7 radio with Spectra synthesized RF module. I also recently acquired a Futaba FP-T7UAF radio system. I read somewhere a long time ago that Futaba modules could be used in the Prism transmitter (they are physically compatible) -- but I don't want to risk damaging the equipment without further confirmation that they are indeed fully compatible.

I am an avid SMALL devotee, but do most of my flying on my own, as I live in a small rural community. I have a whole abandoned airfield to myself! I build all sizes of models, though over 90% of my building is of the SMALL category. I am a diesel freak from the days when the Mills 1.3 was king of the hill!

I think the sweetest engine I ever owned was the E.D.Racer 2.49cc diesel, which was the powerplant in my Class A teamracer. That was the winner of the National Championships in my native Scotland in 1948.

I eagerly await each SMALLnet posting and never fail to be amazed by the diversity and quality of the content. Please keep up the good work. I apologize for rambling and reminiscing. Can anybody help answer my original question (does anyone even recall what it was!)?

Thanks, Tom Beveridge, Carberry, MB., Canada

Ed Baumgartner <  > submitted:

In response to my request to Thunder Tiger Engines in Taiwan, they sent me DXF format 3-View CAD files of the GP 07, 10 and 15 engines. They look really neat! These can obviously be imported into CAD drawings being drawn up by all our aspirant model designers on SMALLnet. Anyone wanting these files can just drop me a line and I'll e-mail the files to them.

I also wrote to Gig Eifflaender at PAW, but unfortunately they still do their drawings manually on a drawing board, so if you need them in CAD format, the old vernier caliper and micrometer method will have to be employed. I wonder if our Dr. Diesel has any of these drawings?

If there are any other SMALL engine DXF CAD files drifting around out there that are available for insertion into my engine library, I would be most grateful.

As always, the SMALLnet postings are eagerly awaited each day, they're the only good reading around. 300th birthday this week! Another milestone.

Kind Regards, Ed Baumgartner

Bill Wells <  > asks:

My inexperience with 'SMALL' must be showing - I need some help to get my Clancy 'Yardbee' percolating. I am using the electric motor pack from Clancy: MG1 motor with 4.8:1 gear drive and 7.25 x 4 prop.

The weight of the plane ready to fly is about 13 ounces. I tached the motor at 5800 rpm with a 6-cell 350 mAH battery. The problem is that it will not maintain level flight, let alone climb. Any suggestions, observations, or advice from someone who has used this combination would be most welcome.

Bill Wells Heber Springs, Arkansas