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Cermark F16 w/ air retracts?

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Old 06-19-2006, 01:28 AM
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kmtranmd
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Default Cermark F16 w/ air retracts?

Anyone tried the latest Cermark offering of the F16 complete with air retracts?? I'd like to try this newest setup but don't know how good their air system is.
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Old 06-19-2006, 08:25 AM
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Default RE: Cermark F16 w/ air retracts?

These are just now hitting the streets.

But the one I have dealt with ........ the retracts look very nice. Real nice product, designed FOR the plane, solid heavy wire struts. The whole system integrates in to the plane easily.

A few folks are considering the landing gear package for the turbine version - just to include the scale looking struts and wheels - some want the brakes too. But the jury is still out on that.
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Old 06-19-2006, 10:35 AM
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Default RE: Cermark F16 w/ air retracts?

Hi Bob,,, i have the new set up ,,F-16 from Cermark,,, i was delayed in my maiden on the 13 th',,,,and was going to maiden on the 17th,,, small things caused the delay---bugs needed worked out,,, so now I am ready for maiden flight, when the weather clears up,,, as for the retracts ,,,, these are the best set of retracts i've seen,,, there bigger in diameter compared to the 3/16 ths wire,,, really robust ,,,nice wheels too,,, the air system works really good for me,,,
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Old 06-19-2006, 11:49 AM
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Default RE: Cermark F16 w/ air retracts?

(looks like you have some neighbors you dont want peeking through the fence )
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Old 06-19-2006, 02:14 PM
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Default RE: Cermark F16 w/ air retracts?

The mech gear on the previous version worked well except for the nice looking but poorly made wheels. The tires come off the alum hubs real easy on grass runway we use. I had to dump them for the cheesy Dubro wheels that stay on the hub better.
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Old 06-19-2006, 02:58 PM
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Default RE: Cermark F16 w/ air retracts?


ORIGINAL: bob27s

(looks like you have some neighbors you dont want peeking through the fence )
neighbors are nice to have ,,, but you don't need them watching-- the price is right-- with you in your living room,,,, if you know what i mean [>:],,, occasionally i see an eye or two.. but the tarp usually does the job well...
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Old 06-19-2006, 06:36 PM
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Default RE: Cermark F16 w/ air retracts?

I just had my LHS order the F16 for me. They have them in stock, even option for General Dynamics finish instead of the usual thunderbird. They need to update their web site real bad.
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Old 06-19-2006, 06:37 PM
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Default RE: Cermark F16 w/ air retracts?

Seriously nice looking ship you got there! Keep us posted as to the maiden---

The weather looked purty nice in that pic
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Old 06-19-2006, 08:08 PM
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Default RE: Cermark F16 w/ air retracts?

Very nice looking plane
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Old 06-21-2006, 08:04 AM
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Default RE: Cermark F16 w/ air retracts?

Thanks guys for the comments,,,, I finally did the maiden,,, ,,all went well,, this bird flys exellent, the os .91 pulls her around very well,,, at takeoff,, it pulled up with no issues at all,,, the plane pulled up so fast i think it was a little tail heavy ,, or mabey i was just afraid of a dreaded nose dive ,,, but i had it balanced at 8& 1/2,,,this bird lands soo sweet ,, i think i needed a little left aileron trim,,, and a little down trim ,,, and once i pulled up the retracts [X(]she picked up more speed and leveled out great,,, this is a great plane ,, everything is still in one piece ,, and i hope to get it up into the blue skys once again,,,thanks guys for all the tips on the reinforcements,,,--landing gear----HB-111.....--one more thing,,, upon landing aproach, be sure you use your rudder,,, this thing gets hairy on landings if you don't use it,,, but like i said sweet landings,,,,, ohh yeah, i like
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Old 06-23-2006, 05:40 PM
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Default RE: Cermark F16 w/ air retracts?

i programmed my TX (PCM 10X Heli version) so that in Stunt 2 i have Tailavons, takes care of the loss of aileron control at low speed so you can slow it down to a crawl with the nose up at 30* or so for a scale landing. i also opted for the General Dynamics scheme but went with the Jett 90LX for power. the retract system works great and as mentioned slightly larger then the regular 3/16 size.

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Old 06-24-2006, 01:36 AM
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Default RE: Cermark F16 w/ air retracts?

What is your setup to get it to slow down to crawl for landing. I also use Jett90 with apc 11x9 on the mech retracts version, weighing about 11 lbs and mine always wants to come in hot or it will stall out when I slow it down.
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Old 06-24-2006, 08:36 AM
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Default RE: Cermark F16 w/ air retracts?

sounds like your nose heavy. also that 9 inch pitched prop isn't helping on the slowing down and to get down to a crawl you have to maintain a high AOA so keep in mind, your Not going to be able to go around, it's a wheels on the ground type approach.

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Old 06-26-2006, 07:57 PM
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Default RE: Cermark F16 w/ air retracts?

I just got the plane from the LHS today. The new bird is quite a bit smaller than last year version with mech retracts. This one has only 50" span instead of 55" previous version, and a bit shorter too. I got the General Dynamics finish, wondering if the Thunderbird version is small too. Hummingbird111, do you mind measuring yours since you have the Thunderbird version?? The air system looks high quality, similar to Robart design with all metal housing but lightweight like the Spring Air gears. I'm very impressed with the air retracts. Just disappointed with the smaller size bird, but it does look a little more scale. Positive note will be that it should go vertical like a "homesick angel" with the Jett90L to propel.
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Old 06-26-2006, 09:07 PM
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Default RE: Cermark F16 w/ air retracts?

I think I just found my future RC love. Beautiful jet. A few questions.

I've never dealt with air retracts before, how do they work? Do you just need one servo to actuate
them? How do you get more air in the tanks and how long does each tank last.

Also, what servos are you guys using? How much torque is needed?
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Old 06-26-2006, 10:00 PM
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Default RE: Cermark F16 w/ air retracts?

with the included 308cc air tank i can cycle the gear up/down and get a positive lock for about 14 cycles with the tank at 80 psi, at that point the pressure has dropped to around 20 and with the air line restrictors I've got in use the nose gear would be a questionable lock at the low pressure in flight, the mains wouldn't be a problem to get down and locked. i honestly don't think you'll find a need to cycle it that many times in a single flight, especially with the fuel consumption of the Jett engine you'd be dead sticking long before that many touch and goes.

to fill the tank i use a Robart pump, it's a small hand held 'bicycle' type pump, takes about 60 strokes to get it up to 80 psi. so far so good on my cylinders, no leaks at all. I've never liked the spring loaded pneumatic gears because of the way they slam down, but in case of an in flight leak or split line they'll always go to the down and locked position, i always try to test my gear for leaks ever couple weeks by leaving them in both the extended and retracted positions overnight and seeing if they loose any pressure.

for the servo i used a JR standard 517, you can use a micro low torque if you choose but i needed the extra weight in the tail so i went with the standard size and it worked out at 8" CG with no ballast weight.

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Old 06-26-2006, 10:35 PM
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Default RE: Cermark F16 w/ air retracts?

Whoa! These are the Robart Air "downs"? I thought the air downs were old school like my old Rhom-Air's, especially since Spring-Air and others have made the air up versions (Air keeps them up, lack of air pressure or a leak forces gear down and locked [) Limp gear is a no-go!!!

As mentioned it is just one std servo or mini that flips the switch (Opens air valve) and yes you get many cycles per PSI I go to 60 PSI and get about 9 cycles and my gear will hold air for almost 24 hours.

I do not have this bird but I bet any decent ball bearing servo would be fine based on the weight- I would just run 6V for extra speed and torque- If you will sleep better with tons of torque the Hitec-645MG is 107@ 4.8V and 133oz @6V and they are only $40 each.

If you wanna go digital for faster response and better centering the Hitec 5645MG is only about $48 bucks - and they come with anodized aluminum arms as well as the Heavy dubro style ones-- (and no, I do not work for Hitec)

I really love this ship so let's keep this thread alive with pics
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Old 06-26-2006, 10:43 PM
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Default RE: Cermark F16 w/ air retracts?

Wow,, and all this time i thought 20 psi was too much,,, so you mean that little can --can hold 60 to 80 psi??,, i think with 20 psi i got 4 cycles once mabey 5,,,[]------while i was pumping air ,, i skwinched my eyes just incase the can busted...[X(]
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Old 06-26-2006, 10:49 PM
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Default RE: Cermark F16 w/ air retracts?

call me old school but I prefer a non spring retract because of the speed in which the gear is cycled up/down. the only way I've been able to slow a spring loaded gear down is to put a heck of a bunch of restrictors on all lines and on the forward retracting gears they tend to not want to pull up at flight speeds. if you don't mind that slamming down, sounds like you hit a bird in mid-air, then spring assisted gears are wonderful things. regular checks for leaks and fixing any leak prevents 99% of the necessity of a spring. on a side note, your system should hold air indefinitely, at 120 psi (what i leak test at) mine loose no pressure at all over a 12-24 hr period. over the week between flights mine maintain the pressure they had on last landing.

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Old 06-26-2006, 10:53 PM
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Default RE: Cermark F16 w/ air retracts?

ORIGINAL: hummingbird111

Wow,, and all this time i thought 20 psi was too much,,, so you mean that little can --can hold 60 to 80 psi??,, i think with 20 psi i got 4 cycles once mabey 5,,,[]------while i was pumping air ,, i skwinched my eyes just incase the can busted...[X(]
one of the first set of air retracts i got were with a Byron F-16 and the instruction sheet said to not exceed 160 psi due to the seals in the cylinders, I've used up to 120 for many, many, many yrs and never had a can fail and only due to age have i had a line split and most of the time it's at a connection where it's stretched around a fitting. i also use a silicone oil to lube my cylinder O-rings ever so often and never have any leaks at all.

kc
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Old 06-26-2006, 10:54 PM
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Default RE: Cermark F16 w/ air retracts?

Well aren't you just *****en then

I personally never had problems with the air down versions but only because I am uptight about preflight and everything but if I had a nickel for every landing I have seen where there was not enough air to get them gear down....

If one chooses for scale retract speed just pout a wheel collar on there but test it thoroughly-

I prefer gear that when **** happens they LOCK THE HELL DOWN, not up [:@]
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Old 06-26-2006, 10:58 PM
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Default RE: Cermark F16 w/ air retracts?

doesn't take but a few belly landings and most people wise up and learn to check for leaks, if you like the springs please by all means continue to use them. don't blame a gear for pilot ignorance.

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Old 06-26-2006, 11:15 PM
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Default RE: Cermark F16 w/ air retracts?

I think you guys misread my thread about the gear. The retracts look and feel lightweight like the Spring Air, but it's NOT spring down. You need air both directions. The air valve is just like Robart type. The whole set up is lighter than typical Robart but function like Robart gear.
Hummingbird111, can you measure the span on your plane since you have Thunderbird scheme to see if it's 50" also??
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Old 06-26-2006, 11:18 PM
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Default RE: Cermark F16 w/ air retracts?

One other comment about the servos. I use Futaba S3152 digital that put out 87oz using 6v. You can buy them for $56/pair from Tower. I've used them on 4-5 planes including the F16 for elevators and ailerons with no problems so far.
http://www2.towerhobbies.com/cgi-bin...0&I=LM0523&P=K
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Old 06-27-2006, 12:45 AM
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Default RE: Cermark F16 w/ air retracts?

Permission?

Blame?

See ya--
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