Centurion13

I have several of these beauties and would like to know in which Control Line model they would work best. What engine are they equivalent to? A Cox .10? An OS .15? I am running them with 7-3 props.

Thanks,

Cent13

vauxhall

Here's a Gilbert powered Keil Kraft Phantom . Black Hawk Modelsmarket a kit these days or plenty of free plans on the net if you want to scratch build one. Non aerobatic trainer ( I did manage to loopmy P.A.W.1.5 dieselpowered version), cutie and all around fun flier. All sheet construction builds fast. I've never owned a Gilbert engine, so I can't comment on it's power output..

vauxhall

http://www.rcuniverse.com/forum/m_23...tm.htm#2425279
Anyone who's interested, here's a link toone old KK Phantom thread. A search will find a few others as well.

greggles47

If you're after an aerobatic model for that size you could try the Princess. 36" span designed by Gordon Cornell in the late 1950's. Pretty thing with plenty of wing area, so it should fly really nicely.

http://www.the.elmores.btinternet.co...s/_cat005.html

Regards

Greg

aspeed

I have never had one either, but being made before schneurle porting, I would think a more modern .09 would be about the same. The OS LA .10 would be similar, maybe a bit stronger. Cox never made a .10 that I know of but had a fairly good Tee Dee .09 that would be similar. AP .09 and ASP .12 would be similar, maybe a bit stronger, as well as similar reproduction diesels of that size. As far as a plane, there are so many, A Jr. Satan made lightly, or a Russian F2D combat would be my choice, A sheet wing profile Goodyear racer like a Buster or Shoestring, I think they were 1/12 th scale, would be good if there is pavement to fly from. No stunts with those though.

Jim Thomerson

I've never seen a Gilbert engine run. I would guess they are not very powerful. Any idea how many RPM your 11 is turning with a 7 x 3? That figure would give us a good idea what it compares to,

Centurion13

Well, have not put a tachometer to it but you can see it run in my garage:

http://www.youtube.com/watch?v=onmKTO1KG7I

and I have read that it moves around 8-10,000 rpm. There are a few other demos of this engine on YouTube and I believe one of them puts a tach to the .07 Gilbert (much faster). Again, this is with a 7-3 prop - the stock prop was a 7-4 plastic number, and I have also read that a 7-3.5 (if such a thing exists) would be ideal.

The issue for me is to find a profile C/L plane that uses an engine of this size - say, a .10 or so. I am not going to put it on a Jumpin' Bean - much as I like them, the wing area simply is not enough. I am not the most proficient at building from blueprints, so for me it would be ideal to build from a kit less than 10 years old.

Cent13

skaliwag

My Feedback: (1)

Mine never had the power of and old, worn out Babe Bee

aspeed

I figure it is 14,000 rpm with my method (A# on the synthesizer) 40 mph on a clean plane. Not really that bad, but a Thunder Tiger .10 does that with a 7-4, and an OS LA .10 does 16,200 with a 7-4 which is a bigger load. Really a Jumping Bean would be ok on longer lines like maybe 45 to 50 feet but would be nose heavy. 

Centurion13

I am thinking a Flying Clown from Brodak will fit the bill. They are out of them, but there are other similar frames that will do the job.

I came into three of them from a friend, and bought three more online. So now I just need to get the plane!

Thanks.

Cent13

aspeed

The Clown sounds good. I kind of want one too, I flew a guy's with an LA .15 and it was pretty quick, (Clown Racer)so the .11 would be good.

steve111

I've had a bit of a play with one, and they're nice enough but not that powerful - an Enya 09 or OS 10 is quite a a bit stronger. Any model for about 1.5cc ought to be fine.

Hossfly

Centurion, I flew and messed around with a couple of these engines way back before dirt, around 1965 +/-. They started easily, ran well but were not a "power-house".
You wish to try one out? Easy!

Get a 3x36" relatively hard balsa, preferably 3/16 or lighter 1/4" balsa. Cut the wing at 24", and save the 12" remaining for the fuselage. Use some light 3/32" balsa for the tail feathers or hard 1/16" sheet will work. Make the stab 20-25% area of the wing. Vertical tail as you wish to suit what you want it to look like, but at least 33% of the horizontal stabilizer total, stab and elevator.
Now a bit of 1/32 or even 1/16 ply for doublers forward of the wing TE. If ( I forget) the Gilbert mounts on rails, the fuselage should be at least 3/16 inch thick with the engine just ahead of the wing LE, either sideways for rail mounts under the ply doubler or a good 3/16" to 1/4" ply firewall if radial mounted. A easy tank is a couple balloons tied around a fuel line with a tube inside where you tie it off. Fill with good hand bulb or a syringe found at any animal feed store.
Don't forget a 1/8" ply for the bellcrank usually mounted next to fuse. under the wing.

With some imagination one can build a very nice CL profile or even built up fuse. model for these small engines. Don't forget some 1/16 music wire to fashion gear legs with also mounted at LE of he wing. CG should be 3/4" behind LE of 3" wing.

I can build such as this in some 1 hour or less, no plans needed. Then another couple hours to add a couple coats of dope with some talcom powder mixed, let dry 30 minutes or so, and then sand it down a bit. Brush on a couple coats of color and it will be ready to fly soon. Actually dope needs some time to cure or glow fuel can cause some milky addition to the finish. Have some to prove that when a couple nephews wanted to fly it "YESTERDAY". I keep a few with 1/2 to .19 engines ready for any kid wishing to give it a try in my back yard, up to 65' lines, and up to 40 engines. One is a profile, solid wing, with Fox .19 which is over 16 years old. Has a lot of scars, but solid flier.

Go test those Gilberts. They can provide some real fun.

mikeainia

My Feedback: (1)

The biggest issue that I've heard of with the Gilberts is that the heads are rather fragile - the .07's have the reputation of blowing the glow head on the first run or sometimes even with just a battery hookup, so start with a glow driver turned all the way down.
I made a head for one a long time ago that took a regular Standard Short plug but I've heard also that the stock heads are a very soft aluminum alloy that is difficult to drill and tap.

These engines are still available from somewhere, as are parts and spare heads.

controlliner

I've run my .11's and .07 and they are quite spirited engines with the right prop. I have found that the .11 will except the Cox .15 medallion head and run well. I have also used the glow plug adaptor sold by McDaniels R/C in the 1980's. The ball and socket reset tool for the Cox .09 work on the Gilbert .11 piston with excellent results. You just have to not use the receptacle for the Cox .09 piston.

aspeed

Ya I was going to say, more compression, Nelson plug (or Turbo plug  but the Cox head is great if it fits) open up the carb hole, more nitro....

Centurion13

In the case of the .11, what would be the 'right prop'?

Cent13

controlliner

The best prop is a 7X3.5 Cox Grey or MAS 7X3.5. Lots of wind on this prop.

Dan Vincent

The Gilbert .11 was designed by Fox and is similar to the old Fox Rocket .09.

Glo heads from the Fox Rocket .09, Fox .10 and Hustler .10 will fit the Gilbert .11. The thread is also the same as a Cox .15 glo-head but I'm not sure of the compression ratio.

Too bad they don't make a Cox .15 diesel conversion head so we could convert the Fox, Hustler & Gilbert engines.

dennis

My Feedback: (90)

Dan,

Duke Fox didn't design the Gilbert engines. That was done by Bob Holland and they were made by Dynamic Motors I.E Hi Johnson. Duke did do some screw work for them though. I always thought that Duke had a major part in the engine because of his Rocket 09. Jim Ivy and others have set the record straight for most of us.

Lou Crane

Please keep in mind that these are 3-port layouts, like many of the spark ignition engines of the 1930's/ mid 1940's. The tube sticking up out the back of the cylinder in the photo shows that. It is the air intake, and the rising piston opens the intake port directly through the cylinder wall. This limits RPM potential.

Reed intake engines have a much higher RPM range potential, because the reed stays open only as long as pressure drop inside the case is low enough to keep it open. And they don't "blow back" the intake mix because the reed closes under any positive pressure. The open and close timing is automatic, but might not be exactly as needed.

The 3-port layout intake is open all the time the piston skirt is above the bottom edge of the intake port in the sleeve. The port timing is symmetrical each side of top dead center. Part of the charge drawn into the crankcase most likely blows back out every revolution before the piston closes the port.

Shaft operated rotary valves provide precise, reliable intake timing, which can be optimized for best power.

Long-winded way to say that the Gilbert engines are not in the same category as even severely-worn Cox reed engines... The only one I've handled was heavy, and provided with a "bicycle handlebar bell" monster of a recoil spring starter. (3-port engines run as happily CW or CCW. The starter's pawl prevented clockwise rotation. 3-port spark engine electronics fired the plug ONLY at the right time for counterclockwise rotation. Same reason.)

The best reason to work up a flyable project, in my opinion, is because it will be a challenge. 3-port engines generally started easily (if the electrical side was willing.) Many of them had power so modest you might call it "shy" instead.

Centurion13

An interesting illustration of the power of the internet - there is no way I would have thought to examine the actual function of the Gilbert engine. Thank you.

That said, your comments prompted me to study three-port design. I believe, though I am ready to be set straight, there may not be as much blow-back of the fuel/air charge as you suggest. I have no data to back this up, other than the successful running of the engine and the notion that the inertia of the incoming charge itself may go some way towards resisting blow-back before the downward-traveling piston closes off that port. At any rate, it would appear this type of engine produces what power it has at lower RPMs than a reed or rotary valve engine of similar displacement. At some point the moving piston and the inertia of the air itself will achieve equilibrium.

Yes, the Gilbert .11 probably has only the power of a reed-valve .049 Cox, one of the ordinary Baby Bee versions instead of the hot-rod types. I am unsure as to why Gilbert settled for such a design when engine technology in the early 1960s was already well beyond the performance of the three-port design. The planes powered by these engines were fairly narrow chord, built for looks rather than performance, and heavy in their own right. I have had little trouble starting mine in the correct direction; though there have been a few reverse starts, stopping the engine dead is a simple matter of covering the intake vent with a finger.

The engine mount holes require drilling out, as the screw size a stock engine permits is inadequate for quick, safe mounting without liberal use of washers to spread out the load on the mounts. Also, some loctite seems to be in order for the exhaust stacks, whose single attachment screw seems to want to walk itself out during a run. I discovered this during the test phase - perhaps propeller balancing is in order to reduce the vibration? And someone, somewhere, suggested a bit of steel wool stuffed gently into the exhaust stacks might dampen the noise a bit, but I hesitate to mess with them - backpressure can only reduce the output of this engine, to my mind.

I am betting that a 36 inch wingspan combined with a seven inch chord should provide the lift to counter the weight of the engine, tank and fuel. The result will not be fast, but it will perform aerobatics and represent for a generation of flyers who are passing away with every day.

Thoughts?

Steve

Centurion13

Which props gave you the best performance with the Gilbert .11? I tried getting hold of some 7-3.5 props, but all I could find were Thimble Drome plastic jobs, and after forty years in the package, the darned thing snapped right off as I was flip starting it!

Steve

Lou Crane

Steve,

APC now offers 7 -3.5 props I believe...

As to why select an older, less capable design... They are simpler to machine. They function without fancy machined crankshafts. Less fussy about operation. Precision needed is only the absolutely necessary fits - sleeve and piston - and just the two port types that are there in all our model 2-cycle engines.

As to fuel/air charge inertia extending the intake efficiency? It also takes measurable time to accelerate the charge into the lower 'case. The inertia may somewhat bias the shaft degree location of the beginning and end of the intake-open 'time.' Other intake methods allow the bypasses to open earlier and close soon after the piston passes TDC. With the 3-port layout, much of the time the piston would have been compressing the charge for the next bypass period, its port is still open through the intake.

Urgent interruption at this end, now, but I think I got my ideas in. Thanks for your comments!

Jim Thomerson

I have an Italian copy of the Cox 7 x 3.5 in some fairly hard white material. I have picked up some black rubber ducky type Cox 7 x 3.5 props off Ebay and have found them very satisfactory and almost indestructible. I've never had any problem with the grey 7 x 3.5 props, but threw blades off two 8 x 4 Cox grey props on an ST G20-15 diesel. I have run them on glow engines and smaller diesels without any problem.