Club A.C. Gilbert
09-14-2013, 08:51 PM
#26
Thread Starter
Dennis, there was a gentleman in one of the forums, of which I cannot recall, that within the past year posted results of these plug adapter heads. He took those adapters, and after measuring the volume of the other more powerful higher compression heads, proceeded to mill the flange contact area until he had the same volume. With plug in place, found he got similar RPM's, close enough to verify it was not the plug adapter concept that was faulty; rather the design.
Regarding my uses, I am not into racing or stunt competition. The slight loss of power for sport modeling use is made up for by judicious building (lighter) and model selection. These Gilberts weren't powerhouses to begin with and the right model they will still do fine with the plug adapters.
Recently I put a 40" foam Sureflite Cessna 180 2 channel RC with Norvel .061 Big Mig CL into the air with the Mecoa .049 plug adapter. It moved the Cessna through the air with sufficient authority to fly in the windy conditions of Clovis, NM, certainly better than with a Cox .049 Black Widow. So yes, may have lost a little in RPM, but this is a cabin sport model, not a pattern plane.
Those into competing and wringing out the last ounce of power will probably want to look at other solutions. Anyway, my 2 cents, for what its worth.
Regarding my uses, I am not into racing or stunt competition. The slight loss of power for sport modeling use is made up for by judicious building (lighter) and model selection. These Gilberts weren't powerhouses to begin with and the right model they will still do fine with the plug adapters.
Recently I put a 40" foam Sureflite Cessna 180 2 channel RC with Norvel .061 Big Mig CL into the air with the Mecoa .049 plug adapter. It moved the Cessna through the air with sufficient authority to fly in the windy conditions of Clovis, NM, certainly better than with a Cox .049 Black Widow. So yes, may have lost a little in RPM, but this is a cabin sport model, not a pattern plane.
Those into competing and wringing out the last ounce of power will probably want to look at other solutions. Anyway, my 2 cents, for what its worth.
09-14-2013, 08:57 PM
#27
Thread Starter
09-15-2013, 04:37 AM
#28
earlwb, I view model plane building unto those who build sand castles on the beach. It is an art form, beautiful to behold, but like the castle, eventual succumbs to the elements. If I end it upon encounter with the terra firma, at least I appreciated the beauty while it was still alive.
Ken
09-15-2013, 06:00 AM
#29
I have used glow plug adapter heads off and on with 1/2a engines over the years. Yes it does affect the performance. But if you are not going for all out maximum performance then it is not a problem. The problem most of the time is the adapter head doesn't have a well done combustion chamber and it tends to have less compression with the glow plug adapter versus the glow head. Also the glow plugs usually have a more deep or larger size hole for the glow plug coil element than there is on the glow heads. The little tiny 1/2a and smaller engines are very sensitive to small combustion chamber volume changes that affect the compression ratio of course. If you are one of those people wanting every extra RPM you can get out of a model engine, then you would not be looking at using a Gilbert engine on anything in the first place.
The Gilbert engines are actually a marvelous design The engine designers wanted a easy to use engine that a newbie or neophyte could get running without a lot of trouble or hassle or help for that matter. Using a piston controlled intake port design supports that as it allows for more mild port timing making for a easier to start and run engine. Pretty much all of the easiest to start types of engines use that kind of a intake induction method. Motorcycles and cars (with 2 stroke engines) used the same method too. Safety was considered with the rear mounted needle for adjusting the engine that helps keep fingers farther way from the propeller. The rear mounted needle assembly is more protected from being damaged or broken in crashes too. The upward facing intake made it relatively easy to put a finger over the hole to choke the engine for priming too. Most planes had a bit of a recess in the fuselage there where one could reach the intake to choke the engine easily as well. The more robust crankcase better survived those crashes as well. The engine was designed to run forward or backwards as needed for different airplanes. But such a design doesn't have the performance or power of a more modern design per se, but what they did was increase the engine displacement to compensate for the design. Thus the .07 was equivalent in power to a good strong running .049 at the time. Their competition was reed valve Cox .049's (maybe not as maybe Cox .049's may not have been on the scene yet), some Wen Macs, McCoys, and Comet .07 engines (this may have been late on the scene too) at the time. So the Gilbert engine didn't run any worse than the other brand engines of that era.
The Gilbert engines are actually a marvelous design The engine designers wanted a easy to use engine that a newbie or neophyte could get running without a lot of trouble or hassle or help for that matter. Using a piston controlled intake port design supports that as it allows for more mild port timing making for a easier to start and run engine. Pretty much all of the easiest to start types of engines use that kind of a intake induction method. Motorcycles and cars (with 2 stroke engines) used the same method too. Safety was considered with the rear mounted needle for adjusting the engine that helps keep fingers farther way from the propeller. The rear mounted needle assembly is more protected from being damaged or broken in crashes too. The upward facing intake made it relatively easy to put a finger over the hole to choke the engine for priming too. Most planes had a bit of a recess in the fuselage there where one could reach the intake to choke the engine easily as well. The more robust crankcase better survived those crashes as well. The engine was designed to run forward or backwards as needed for different airplanes. But such a design doesn't have the performance or power of a more modern design per se, but what they did was increase the engine displacement to compensate for the design. Thus the .07 was equivalent in power to a good strong running .049 at the time. Their competition was reed valve Cox .049's (maybe not as maybe Cox .049's may not have been on the scene yet), some Wen Macs, McCoys, and Comet .07 engines (this may have been late on the scene too) at the time. So the Gilbert engine didn't run any worse than the other brand engines of that era.
Last edited by earlwb; 09-15-2013 at 06:05 AM. Reason: typo correction
09-15-2013, 12:12 PM
#30
Thread Starter
Actually, if one is into performance, the modern battery systems, ESC's and outrunner electric motors have surpassed the half-A's regarding power and performance. I like the Gilbert engines because they are representative of the mid 1950's to 1960's era. Properly treated, they will perform well and provide many hours of satisfaction. They have the vintage look to them, which look sharp on a plane of that vintage.
09-15-2013, 03:17 PM
#31
earlwb, I view model plane building unto those who build sand castles on the beach. It is an art form, beautiful to behold, but like the castle, eventual succumbs to the elements. If I end it upon encounter with the terra firma, at least I appreciated the beauty while it was still alive.
I believe that is a pretty accurate statement.
09-15-2013, 04:36 PM
#32
Thread Starter
earlwb, speaking of the accuracy of that statement, this weekend I witnessed a large scale gas plane similar to the Extra (must have been at least 1/5th scale), which upon flying upwind at about 100 feet elevation about 200 yards out, lost the radio and with what appeared to be full left rudder with full throttle, dipped left and smashed headlong into the hard packed soil. Due to the high quality ARF light building with structural lightening holes, the nose of it to the wing was reduced to to kindling fragments. Pilot said he only had 6 flights on it. It sort of reminded me of how converted Guillow rubber powered stick and tissue kits will do similar on a high speed dive.
09-15-2013, 06:11 PM
#34
Thread Starter
09-17-2013, 04:22 AM
#35
I was rereading the article about Gilbert Engines that was published in Model Engine Collectors' Journal, Volume 30, #5, issue 173,(September 2005).
Mr Effinger stated that they made about 500.000 Gilbert engines in the space of about two years and around 300,000 of those engines were for the Wing Thing. The Wing Thing used the 07 engines. So since the market was ending at the time, they wound up with a lot of engines and parts left over.
The last known advertisement for the engines was for the Thunderjet .074 engine at $1.00 US in Model Airplane News in 1970. In 1969 they were selling the .074 engines for $2.99 US.
Roger Schroeder did some performance tests with the engines and got these results.
07 engine
7-4 plastic prop 10,500
7-3 wood prop 13,000
6-4 wood prop 14,500
8-4 wood prop 7,500
for the 11
9-6 wood prop 6500-7500 unsteady
8-6 wood prop 9500 unsteady
804 wood prop 10,000 unsteadyness attributed to intake bore
Model Engine world in 1994 got these numbers:
15% nitro glow fuel the 7 modified to use a replacement glow plug
7-3 APC prop 9,300
6-5 Graupner 10,400
6-4 Grapuner 11,200
6-3 Master Airscrew 12,000
for the 11 using a original glow head
7-5 Graupner 9,100
7-4 APC 13,700
7-3 APC 15,000
Mr Effinger stated that they made about 500.000 Gilbert engines in the space of about two years and around 300,000 of those engines were for the Wing Thing. The Wing Thing used the 07 engines. So since the market was ending at the time, they wound up with a lot of engines and parts left over.
The last known advertisement for the engines was for the Thunderjet .074 engine at $1.00 US in Model Airplane News in 1970. In 1969 they were selling the .074 engines for $2.99 US.
Roger Schroeder did some performance tests with the engines and got these results.
07 engine
7-4 plastic prop 10,500
7-3 wood prop 13,000
6-4 wood prop 14,500
8-4 wood prop 7,500
for the 11
9-6 wood prop 6500-7500 unsteady
8-6 wood prop 9500 unsteady
804 wood prop 10,000 unsteadyness attributed to intake bore
Model Engine world in 1994 got these numbers:
15% nitro glow fuel the 7 modified to use a replacement glow plug
7-3 APC prop 9,300
6-5 Graupner 10,400
6-4 Grapuner 11,200
6-3 Master Airscrew 12,000
for the 11 using a original glow head
7-5 Graupner 9,100
7-4 APC 13,700
7-3 APC 15,000
Last edited by earlwb; 09-17-2013 at 04:24 AM. Reason: typo correction
09-17-2013, 04:48 AM
#36
Thread Starter
With a half million of those engines manufactured, you'd wonder what happened to all of them. I sometimes wonder if they wound up being recycled for the aluminum. I also gathered that these engines are most happy with 6x3 or 6x4 for the .07, and 7x3 or 7x4 for the .11 reflected in the data, which also mirrors the recommended props on the card instructions that came with the Tower Hobbies purchased engines. Going on Peter Chin's Nov. 1966 MAN report on the Enya .09-III, RPM wise (12,600 on Tornado 7x4 prop using 5% nitro versus Gilbert .11 at 13,700 on APC 7x4 using 15% nitro), the Gilbert .11 seems to compare favorably power wise.
In other words, the Gilbert .11 can be used in planes that use a mild (non-Schneurle non-Tee Dee) .09 engine.
In other words, the Gilbert .11 can be used in planes that use a mild (non-Schneurle non-Tee Dee) .09 engine.
Last edited by GallopingGhostler; 09-17-2013 at 04:51 AM.
09-17-2013, 06:25 AM
#37
Actually if you run and use one of the Gilbert engines, they perform fairly well. They will fly airplanes OK. At the time the engines were comparable to the other 1/2a or A class engines being used.
Well Gilbert jumped into model airplanes in a big way. Producing in large quantity is the way to lower costs, but it ties up money in inventory though. Thus Gilbert being caught on the tail end of the control line fad that was sweeping the country at the time wound up with lots of inventory on hand as people weren't buying the CL ready to fly planes, etc. like they did before. I think the big selling period was from just after WWII 1945 through about 1960 or so up to maybe 1965, when everyone was all excited about it. Kids were not watching television so they would go outside to play. Sports like softball, baseball, basketball were popular then. Tether cars, tether boats and rail cars were all the rage right after WWII too. Gilbert just made the mistake of getting into control line at the tail end of it all. Then television started impacting on what people did in a big way. So having all that money tied up in inventory hurt them a lot.
Yes they made a lot of engines, which is why the engines are still fairly common and easily found even in new un-run condition. Actually they are just now starting to see the end of the Gilbert engine parts and engines to fix up and sell. the guy on Ebay who sells under the SB1Photo alias can see the bottom of the pallets of engines and parts that he bought years ago. He cleans up and fixes engines to sell in his store. When Polks stopped they had pallets and barrels full of engines and parts. Many engines still in their packaging ready to sell too. But aftermarket people have made a big dent in selling them off over the years. The main problem was having the engines sit for a long time and the castor oil congealed making them freeze up. Yes it is easy to unfreeze them but it was not cost effective for a company to do so.
The little Fox 1/2a engines were made in large quantities too, but not as much as Gilbert though. There used to be someone fixing up to sell Fox 1/2a engines, but he sort of retired, and no one else has come forward to take over for him.
There is still someone selling the OK 1/2a engines out there too. I did buy a couple of them a few years ago. They make the engines up out of leftover parts that they got.
During its peak, Cox had their ready to fly 1/2a airplanes, car, helicopters in just about every retail outlet in America you could think of. They were everywhere. The Cox Engines Canada company has acquired much of the Cox engine inventory and they make engines from the parts leftover too. Plus they make new parts as needed. But they cannot have the parts made in huge quantities like Cox did at the time. Cox was making a million or so engines a year at their peak.
Well Gilbert jumped into model airplanes in a big way. Producing in large quantity is the way to lower costs, but it ties up money in inventory though. Thus Gilbert being caught on the tail end of the control line fad that was sweeping the country at the time wound up with lots of inventory on hand as people weren't buying the CL ready to fly planes, etc. like they did before. I think the big selling period was from just after WWII 1945 through about 1960 or so up to maybe 1965, when everyone was all excited about it. Kids were not watching television so they would go outside to play. Sports like softball, baseball, basketball were popular then. Tether cars, tether boats and rail cars were all the rage right after WWII too. Gilbert just made the mistake of getting into control line at the tail end of it all. Then television started impacting on what people did in a big way. So having all that money tied up in inventory hurt them a lot.
Yes they made a lot of engines, which is why the engines are still fairly common and easily found even in new un-run condition. Actually they are just now starting to see the end of the Gilbert engine parts and engines to fix up and sell. the guy on Ebay who sells under the SB1Photo alias can see the bottom of the pallets of engines and parts that he bought years ago. He cleans up and fixes engines to sell in his store. When Polks stopped they had pallets and barrels full of engines and parts. Many engines still in their packaging ready to sell too. But aftermarket people have made a big dent in selling them off over the years. The main problem was having the engines sit for a long time and the castor oil congealed making them freeze up. Yes it is easy to unfreeze them but it was not cost effective for a company to do so.
The little Fox 1/2a engines were made in large quantities too, but not as much as Gilbert though. There used to be someone fixing up to sell Fox 1/2a engines, but he sort of retired, and no one else has come forward to take over for him.
There is still someone selling the OK 1/2a engines out there too. I did buy a couple of them a few years ago. They make the engines up out of leftover parts that they got.
During its peak, Cox had their ready to fly 1/2a airplanes, car, helicopters in just about every retail outlet in America you could think of. They were everywhere. The Cox Engines Canada company has acquired much of the Cox engine inventory and they make engines from the parts leftover too. Plus they make new parts as needed. But they cannot have the parts made in huge quantities like Cox did at the time. Cox was making a million or so engines a year at their peak.
Last edited by earlwb; 09-17-2013 at 06:31 AM. Reason: typo correction
09-17-2013, 10:57 AM
#38
Thread Starter
Yes, I remember SB1Photo a few years ago was selling various flavors of the Gilbert .07 engine. It looks like he ran out of those and now has the .11's to sell, along with .11 glow heads.
I've got a 1959 Berkeley Impulse 45" wingspan single channel pylon racer kit. On the plans it shows a Fox .09 Rocket side port engine. I'm thinking of making this kit a 2 channel (rudder & elevator), with a Sonic full down elevator actuated fuel cut off switch to chop the engine if required. With a 2 ounce fuel tank, it ought to provide about 8 minutes of flight with the Gilbert .11 Thunderhead.
http://www.oldmodelkits.com/index.php?detail=13398
Shows a photo of the box and a description of the plane, the Henry Struck design and Bill Effinger's ownship of Berkeley. I've added photos of the how the Gilbert .11 would fit on the plans and Berkeley die crunching of the day.
Gilbert .11 would be a good shoe-in for the Fox .09 Rocket engine.
I've got a 1959 Berkeley Impulse 45" wingspan single channel pylon racer kit. On the plans it shows a Fox .09 Rocket side port engine. I'm thinking of making this kit a 2 channel (rudder & elevator), with a Sonic full down elevator actuated fuel cut off switch to chop the engine if required. With a 2 ounce fuel tank, it ought to provide about 8 minutes of flight with the Gilbert .11 Thunderhead.
http://www.oldmodelkits.com/index.php?detail=13398
Shows a photo of the box and a description of the plane, the Henry Struck design and Bill Effinger's ownship of Berkeley. I've added photos of the how the Gilbert .11 would fit on the plans and Berkeley die crunching of the day.
Gilbert .11 would be a good shoe-in for the Fox .09 Rocket engine.
Last edited by GallopingGhostler; 09-17-2013 at 11:00 AM. Reason: Additional photos and explanation.
09-17-2013, 11:21 AM
#39
Thread Starter
There is still someone selling the OK 1/2a engines out there too. I did buy a couple of them a few years ago. They make the engines up out of leftover parts that they got.
During its peak, Cox had their ready to fly 1/2a airplanes, car, helicopters in just about every retail outlet in America you could think of. They were everywhere. The Cox Engines Canada company has acquired much of the Cox engine inventory and they make engines from the parts leftover too. Plus they make new parts as needed. But they cannot have the parts made in huge quantities like Cox did at the time. Cox was making a million or so engines a year at their peak.
09-17-2013, 11:25 AM
#40
That would be really cool. The plane is almost made for that Thunderhead engine. It is hard to imagine that they were really pylon racing with single channel radio controlled planes back then. Even with the rudder and elevator linked.
09-22-2013, 05:51 PM
#41
Thread Starter
I can see how one could do it, earlwb. One would shim the wing based on what the prevalent winds were for the day. This would keep the plane from excessively climbing. Then by varying the radius of the turns would determine the altitude one maintains. Elevator would have to be tweaked to perform this, but being a prolific single channel flier 40 years ago, got to where I could put that plane where I wanted it, it is just practice. So, inasmuch as it seems as an impossibility, it is quite possible to someone experienced in single channel flight.
09-22-2013, 06:36 PM
#42
Dennis, yes, Davis did make 12 diesel heads for the Cox TD .09.
I have one.
Here is a picture of a Mecoa Cox .09 head on a TD and the Davis head on a Cox .09 Medallion with Tatone clam shell muffler.
Diesel engines usually turn a bit slower but you can increase prop diameter for more thrust.
I have one.
Here is a picture of a Mecoa Cox .09 head on a TD and the Davis head on a Cox .09 Medallion with Tatone clam shell muffler.
Diesel engines usually turn a bit slower but you can increase prop diameter for more thrust.
09-22-2013, 06:43 PM
#43
One has to be careful converting glow engines to diesel. The crankshafts and or connecting rod and piston tend to be the weak link. Some engines didn't do well converted to diesel as the crankshafts tended to break or the rods or pistons failed. That is likely why DDD only made a few heads for a certain engine or just one head. I don't think that the Gilbert engine's crankshaft would withstand the added stress being run as a diesel, but there is only one way to find out though.
09-22-2013, 06:52 PM
#44
Bob Davis said he was worried about the crank survivability of the Cox .09 TD with diesel power so he cancelled the project.
The Gilbert was not a super high speed engine like the Cox TD .09 so it might be safer under diesel power. I'm sure someone could cobble up a stronger rod, if needed.
Somewhere I saw a Gilbert .11 converted to ignition and I've always wondered how that one ran.
It would just be neat to try a dieselized Fox .09, 10 or Gilbert .11
The Gilbert was not a super high speed engine like the Cox TD .09 so it might be safer under diesel power. I'm sure someone could cobble up a stronger rod, if needed.
Somewhere I saw a Gilbert .11 converted to ignition and I've always wondered how that one ran.
It would just be neat to try a dieselized Fox .09, 10 or Gilbert .11
09-25-2013, 03:53 AM
#45
I was lucky enough to be able to acquire one of the Gilbert .11 Thunderhead engines that was converted to spark ignition. Reginald Luycx in Belgium was the person who did the conversion. He based his conversion on the article written by Neville Palmer in Model Airplane World 1996.
09-25-2013, 04:41 AM
#46
Thanks for posting those pictures of a Gilbert .11 converted to ignition.
I've also seen a K&B Torpedo .09 conversion with a gold head and Herb Birmingham used to make his own timer castings to convert a McCoy .098 to ignition. Herb lived in Stoney Point, NY and I think he said he made five or six McCoy .098 conversions.
I've also seen a K&B Torpedo .09 conversion with a gold head and Herb Birmingham used to make his own timer castings to convert a McCoy .098 to ignition. Herb lived in Stoney Point, NY and I think he said he made five or six McCoy .098 conversions.
