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Old Sep 25, 2013, 03:22 PM
tom
tomme21's Avatar
USA, LA, Natchitoches
Joined Apr 2004
1,599 Posts
eurofighter nose retract

im looking for that part, hobby lobby does not handle it anymore and is discontinuing the plane. where can i find this nose retract please?

im afraid to "mix in" another brand retract as most times they wont work

thanks
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Old Sep 26, 2013, 03:06 AM
Hope is not a Strategy
Lojik's Avatar
Australia, VIC, Caroline Springs
Joined Apr 2011
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Researching some electric options for a 20-24lb model project (P-51) the kit came with pneumatic retracts (2 mains and 1 tail) and stuts so i have a few options:

buy actuators from someone like wingspan or Robart and replace the cylinders with the actuators myself, this would cost around $300 from either supplier

buy whole new units including struts and wheels from someone like ESM, this would cost around $300 as well but wont fix the tail so I would have to probably make the tail a fixed tail and not retracting

Send the retracts that came with the kit to someone like down and locked and get them converted, wingspan also do this for an extra $100, will probably be about $180 more than buying the actuators separately but they will be do all the hard work and make sure its sweet.

Thoughts anyone, have i got any other options?

Jack
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Old Sep 26, 2013, 08:09 PM
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United States, TX, Kerrville
Joined Oct 2003
2,292 Posts
Quote:
Originally Posted by Lojik View Post
Researching some electric options for a 20-24lb model project (P-51) the kit came with pneumatic retracts (2 mains and 1 tail) and stuts so i have a few options:

buy actuators from someone like wingspan or Robart and replace the cylinders with the actuators myself, this would cost around $300 from either supplier

buy whole new units including struts and wheels from someone like ESM, this would cost around $300 as well but wont fix the tail so I would have to probably make the tail a fixed tail and not retracting

Send the retracts that came with the kit to someone like down and locked and get them converted, wingspan also do this for an extra $100, will probably be about $180 more than buying the actuators separately but they will be do all the hard work and make sure its sweet.

Thoughts anyone, have i got any other options?

Jack
What's wrong with the Robarts?

CR
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Old Sep 26, 2013, 09:00 PM
Hope is not a Strategy
Lojik's Avatar
Australia, VIC, Caroline Springs
Joined Apr 2011
1,480 Posts
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Originally Posted by Charley38 View Post
What's wrong with the Robarts?

CR
Nothing, I have no issue with Robarts, the only downside for us here in Australia is cost and I would like to see if there are other options for this size model.

Unless you are referring to the set I already have, which are NOT Robarts, they are Phoenix Models air type and I would prefer not to go down the air route out of personal preference. The frames of the ones I have though look OK, so I may end up getting an electric conversion kit from Robart with an extra actuator for the tail unit. Will need to contact them to find out the cost to ship and the size of their actuators.

Jack
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Old Sep 27, 2013, 01:35 AM
Corsair Captain
United States, AZ, Mesa
Joined Oct 2010
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Hobby King has some with 10mm pins. What size are your struts diameter?
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Old Sep 27, 2013, 01:55 AM
Hope is not a Strategy
Lojik's Avatar
Australia, VIC, Caroline Springs
Joined Apr 2011
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Quote:
Originally Posted by garryk View Post
Hobby King has some with 10mm pins. What size are your struts diameter?
I saw those, I have a mate testing them out now, will go off his feedback as i'm apprehensive relying on $25 retracts in a $1800 model
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Old Sep 27, 2013, 02:48 AM
Too windy to fly? Lets surf
w1nd6urfa's Avatar
Athens, Greece
Joined Oct 2008
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Quote:
Originally Posted by Lojik View Post
I saw those, I have a mate testing them out now, will go off his feedback as i'm apprehensive relying on $25 retracts in a $1800 model
That's the correct approach.
I would go spring-air and have peace of mind. In my humble opinion there are no reliable electric retracts when you cross the 18-20 lbs barrier.

And when I say reliable I mean 99,99%, 90% won't do!

But if you insist to experiment, please do and post results.
In Europe people with heavy warbirds use Eurokit, I know they are expensive but they are supposed to be good.
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Old Sep 27, 2013, 03:11 AM
Hope is not a Strategy
Lojik's Avatar
Australia, VIC, Caroline Springs
Joined Apr 2011
1,480 Posts
Quote:
Originally Posted by w1nd6urfa View Post
That's the correct approach.
I would go spring-air and have peace of mind. In my humble opinion there are no reliable electric retracts when you cross the 18-20 lbs barrier.

And when I say reliable I mean 99,99%, 90% won't do!

But if you insist to experiment, please do and post results.
In Europe people with heavy warbirds use Eurokit, I know they are expensive but they are supposed to be good.
My thoughts are if I can swap the cylinders for good quality actuators I should be sweet as the retracts in the kit are designed for the model so should be suitable to take the load, failing that the ESM branded ones I know from first hand experience (as long as they are G3) are capable of handling the loads and seem to have a good reliability score.

Almost any system will break from a super hard landing so I'm more concerned about reliability.

The times are changing my friend, I know its slow but I can see the future of air retracts dwindling as the cost reduces and performance of the electric retract market grows

Happy to experiment at this level but anything bigger (100cc plus) I would still be using gas and using top of the line gear.

I will certainly be testing what ever route I choose allot before she flys, no once up once down then all good, 10 cycles back to back in different positions 2 or 3 times over different days.

Will post what I come up with in the end.
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Old Sep 28, 2013, 04:22 PM
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United States, WI, Chetek
Joined Jul 2011
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I decided to purchase a set of Hobby King large retracts. http://www.hobbyking.com/hobbyking/s..._10_12kg_.html

I also have a set of Wingspan retracts that I originally installed in my B-25. They were $275 for a set of three. The Hobby King are $28 each. Even if I add $30 for shipping that is $114 for a set of three.

Here are some pictures of the internals of both retracts. The differences are as follows, from my observations at least...
The Wingspan's trunnion appears to be heavier duty than the HK. For some reason HK decided to cast their trunnion with recesses moulded into it. Seems that would take away from the strength, but that has yet to be determined.

The jack screw has different threads between the two. The Wingspan is more like an Acme thread whereas the HK is a standard 3mm thread. Both work fine.

The lead screw of the HK looks like it is one piece all the way into the gear train. The Wingspan has a coupling with a set screw that connects the gear train to the jack screw. This was an issue for me because on of my Wingspan retracts would run but the gear would not move. Turns out this set screw loosened up and allowed the output shaft to turn inside the jackscrew coupling. Two weeks lost shipping in and getting it back.

Neither jack screw is supported at the long end by a bearing. The Wingspan has a place for a bearing but not installed. That must be the $175 each option.

The motor on the HK is literally twice as big as the Wingspan. 26mm long for the HK, 15mm for the WS. Both are about 15mm wide.

The HK has micro switches that limit travel for the trunnion. I have also heard that there is an overload cutout that kicks in after 8 seconds, but it draws 2.5 during that period. The WS only has circuitry which senses a dramatic rise in amp draw and stops the motor. No micro switches. You decide which one is better.

Gear train between the two look almost identical except the HK is larger.

The big drawback to the HK is the stupid 10mm hole in the trunnion. Robart Robostruts are about 12.5mm in diameter so they do not fit. I easily made up some adapters on the lathe that will accept the Robostrut and then insert into the HK trunnion. I attempted to make a completely new trunnion out of aluminum bar stock but without a vertical mill, it was very difficult. It took a lot of time to make one, and it did not fit 100% great so I abandoned the idea for now. If I had a mill, it would not take me long to create a new trunnion that would fit the Robostrut and be more stout.
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Old Sep 28, 2013, 05:41 PM
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Joined Jun 2002
921 Posts
SEMP Electric Retracts

Here is a pic of the retracts I make. This set is made for the Nitromodels Falcon-120. It's all made of 100% aircraft grade aluminum and stainless steel. The trunion bock is machined out of 7075, the rest of the aluminum is 6061-T6. The strut is stainless steel, and mounts into the trunion block, and is held in place by the dowel pin that is also the piviot for the assembly. The strut is shock absorbing, and the wheel hub also has an air operated brake. The wheel hub has ball bearings, and is locked into the hub with a sholder bolt. The rubber tire comes mounte onthe hub. The motor operates from 5 Vdc to 15 Vdc. Speed reduction is accomplished by using a 40:1 planetary gear box, not a linear gear train like all the others use. The lead screw is 10-24 stainless, and is pin mounted to the gear box shaft.

Now for the electronics
A microprocessor controls the operation of the retracts and the built in programable Gear door servo drive. No other manufactures of electric retracts do this yet. There is no limit switches. The microprocessor shuts the motor off in 30 microseconds, when the current reaches a certain level. Another feature is, if the gear are stored in the up position, which is usually the way the model is transported in your car. All you have to do is apply power to the retract and they come down and stay that way, even after power is turned off, or until power is turned back on again and the receiver pulse is applied. The gear door sequencer is programable for the type ( standard or P51) and the end limits are set, as is direction. Unfortuntionaly I can't compete with chineese junk. But a three gear set is $375, and you get everything you need.
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Last edited by LJE4357; Sep 28, 2013 at 05:44 PM. Reason: add pic
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Old Sep 28, 2013, 07:07 PM
Hope is not a Strategy
Lojik's Avatar
Australia, VIC, Caroline Springs
Joined Apr 2011
1,480 Posts
Quote:
Originally Posted by JurassicJet View Post
I decided to purchase a set of Hobby King large retracts. http://www.hobbyking.com/hobbyking/s..._10_12kg_.html

I also have a set of Wingspan retracts that I originally installed in my B-25. They were $275 for a set of three. The Hobby King are $28 each. Even if I add $30 for shipping that is $114 for a set of three.

Here are some pictures of the internals of both retracts. The differences are as follows, from my observations at least...
The Wingspan's trunnion appears to be heavier duty than the HK. For some reason HK decided to cast their trunnion with recesses moulded into it. Seems that would take away from the strength, but that has yet to be determined.

The jack screw has different threads between the two. The Wingspan is more like an Acme thread whereas the HK is a standard 3mm thread. Both work fine.

The lead screw of the HK looks like it is one piece all the way into the gear train. The Wingspan has a coupling with a set screw that connects the gear train to the jack screw. This was an issue for me because on of my Wingspan retracts would run but the gear would not move. Turns out this set screw loosened up and allowed the output shaft to turn inside the jackscrew coupling. Two weeks lost shipping in and getting it back.

Neither jack screw is supported at the long end by a bearing. The Wingspan has a place for a bearing but not installed. That must be the $175 each option.

The motor on the HK is literally twice as big as the Wingspan. 26mm long for the HK, 15mm for the WS. Both are about 15mm wide.

The HK has micro switches that limit travel for the trunnion. I have also heard that there is an overload cutout that kicks in after 8 seconds, but it draws 2.5 during that period. The WS only has circuitry which senses a dramatic rise in amp draw and stops the motor. No micro switches. You decide which one is better.

Gear train between the two look almost identical except the HK is larger.

The big drawback to the HK is the stupid 10mm hole in the trunnion. Robart Robostruts are about 12.5mm in diameter so they do not fit. I easily made up some adapters on the lathe that will accept the Robostrut and then insert into the HK trunnion. I attempted to make a completely new trunnion out of aluminum bar stock but without a vertical mill, it was very difficult. It took a lot of time to make one, and it did not fit 100% great so I abandoned the idea for now. If I had a mill, it would not take me long to create a new trunnion that would fit the Robostrut and be more stout.
Thanks for the pics Jurassic, does the block rotate close to the control board of the HK, it looks awfully close, is there any protection between the two.

They don't look that bad for the price but still a bit weary of what measures they took in the control board to regulate the retract

Quote:
Originally Posted by LJE4357 View Post
Here is a pic of the retracts I make. This set is made for the Nitromodels Falcon-120. It's all made of 100% aircraft grade aluminum and stainless steel. The trunion bock is machined out of 7075, the rest of the aluminum is 6061-T6. The strut is stainless steel, and mounts into the trunion block, and is held in place by the dowel pin that is also the piviot for the assembly. The strut is shock absorbing, and the wheel hub also has an air operated brake. The wheel hub has ball bearings, and is locked into the hub with a sholder bolt. The rubber tire comes mounte onthe hub. The motor operates from 5 Vdc to 15 Vdc. Speed reduction is accomplished by using a 40:1 planetary gear box, not a linear gear train like all the others use. The lead screw is 10-24 stainless, and is pin mounted to the gear box shaft.

Now for the electronics
A microprocessor controls the operation of the retracts and the built in programable Gear door servo drive. No other manufactures of electric retracts do this yet. There is no limit switches. The microprocessor shuts the motor off in 30 microseconds, when the current reaches a certain level. Another feature is, if the gear are stored in the up position, which is usually the way the model is transported in your car. All you have to do is apply power to the retract and they come down and stay that way, even after power is turned off, or until power is turned back on again and the receiver pulse is applied. The gear door sequencer is programable for the type ( standard or P51) and the end limits are set, as is direction. Unfortuntionaly I can't compete with chineese junk. But a three gear set is $375, and you get everything you need.
Very nice LJE, couple of questions

Do you have a site with these on there we can look at?
What is that white part on the strut?
What are the dims on your units?
Can you custom make the mount to suit a specific flange style
Everything you need, does that include struts and wheels?
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Old Sep 28, 2013, 08:04 PM
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Joined Jun 2002
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Quote:
Originally Posted by Lojik View Post
Thanks for the pics Jurassic, does the block rotate close to the control board of the HK, it looks awfully close, is there any protection between the two.

They don't look that bad for the price but still a bit weary of what measures they took in the control board to regulate the retract



Very nice LJE, couple of questions

Do you have a site with these on there we can look at?
What is that white part on the strut?
What are the dims on your units?
Can you custom make the mount to suit a specific flange style
Everything you need, does that include struts and wheels?
Yes I have a website "www.southeastmodelProducts.com", but its way out of date. About the only thing worth wild is my phone #. It does have pic's of the air operated micro retracts I make. I was the first to make them. I been making custom retracts for about 15 years, and electric for about 3 years now. I also make high performance EDF's.

The white part is not on the strut, it's on the motor. It's heat shrink tubing. It holds the motor wires comming out on the back of the motor, attached to the PC board.

As for dimensions. I only make electric retracts right now for aircraft 10 lbs on up to 60 lbs. I'm not compeating with the imports. Right now I have 4 sizes of the PC board, thatn kinda controls the sizr of the retracts I can make. I do have PC board layout, that removes the control electronics into a seperate enclosure. Now I can make any size retract, and just run the 2 motor wires to the motor on the retract. It also allows me to replace the electronics of other manf. retracts with my electronics. So yes, I can custom make any size retract. In fact I'm making retracts for Sam, who is building a very large Concorde. He has a thread in here in the " Airliner" section. I supply the complete retract if you purchase it with all the options, mainly brakes. If you don't get brakes, then you don't get the wheel unless you order it.

I been in the hobby business since 1985. I have a EE degree withover 50 yr's of electronic experience, 40 years as a design engineer in the High Power Radar Transmitters, and every kind of Power Supply you can think of. I also had 2 years of Machine Shop training in high school, and some kind of machine shop over the last 40 years. I don't know everything, but I do know what I'm doing. The last job I had as a contract engineer, I worked on the largest ESC ever. A 6000 horsepower 3 phase consant torq. dc motor to supply main power to one of our submarines. I also have 2 patten,s register as the designer in my name.

I hope I pass muster.

Larry E.
SouthEast model Products
Orlando Fl. ( In the old RC World)
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Old Oct 06, 2013, 08:16 AM
I Used To Have More Free Time!
Charlotte, NC
Joined Feb 2011
2,023 Posts
Does anyone sell retract pins? I want to upgrade to a 4 mm pin, but can not find any for sale. And of course, the front pin needs to have the groove already cut in for the lock spring to fit into.
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Old Oct 06, 2013, 10:55 AM
Corsair Captain
United States, AZ, Mesa
Joined Oct 2010
2,398 Posts
Piano wire from your local hobby shop and dremmel the grooves.
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Old Oct 06, 2013, 01:24 PM
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United States, TX, Grand Prairie
Joined Nov 2005
5,881 Posts
Quote:
Originally Posted by LJE4357 View Post
...A 6000 horsepower 3 phase consant torq. dc motor to supply main power to one of our submarines....
Is this on 16s or 1600s?

Me things this tech can be used in other forms of propulsion too
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