RE: THE NEW CERMARK F-16 BUILD IT BETTER, STRONGER, AND FASTER!!!  
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All Forums >> RC Airplanes >> Extreme Speed Prop Planes >> RE: THE NEW CERMARK F-16 BUILD IT BETTER, STRONGER, AND FASTER!!!
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RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 10:32:20 AM   
miklos



Posts: 195
Joined: 4/1/2004
From: Meriden, CT, USA
Status: offline 		Did Cermark give you an estimate of when you might get the jet. I tried to order a fuselage about a week ago and was told they were on back order 3 to 6 months!
Hope you don't have to wait that long.

(in reply to k8svrick)
       Post #: 1626

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 11:57:52 AM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline
quote:

ORIGINAL: miklos

Did Cermark give you an estimate of when you might get the jet. I tried to order a fuselage about a week ago and was told they were on back order 3 to 6 months!
Hope you don't have to wait that long.


It shipped last week on the 16th from Anaheim, CA and it's on the FedEx truck out for delivery as I write this message. I'm in Columbus, OH, so it had a bit of a ride.

Hope you get your parts soon. I hate being down waiting for parts. But the demad is apparently high for this plane and replacement parts.

_____________________________

Rick - Columbus, OH
www.ricktressler.com

(in reply to miklos)
       Post #: 1627

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 1:26:43 PM   
gsoav8r


 

Posts: 211
Joined: 1/17/2002
From: Huntersville, NC, USA
Status: online 		Rick,
When you receive your plane, would you be kind enough to tell us all if Cermark has bothered to add an addendum for the CG or update the instructions.
I believe the manual states the CG to be 8.5 inches. But that is wrong and should be 7.5.

Cermark has known about this for at least a year but to my knowledge hasnt addressed the issue.

Thanks,
James

_____________________________

Revver Bro #202

(in reply to k8svrick)
       Post #: 1628

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 1:59:24 PM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline 		Hi Jim,

I sure will.

That's hard to understand. I think the good thing about these advanced aircraft like the F-16 is that a newbie to RC wouldn't make it their first ship and assume they needed to add 2 oz. of lead to the aft section of the plane. With the knowledge behind them, the more expereinced pilot would, as one of the fellow members here noted, seem to think that's just not right and question it like he did. Good for him, too. One should never have to add that much weight to make an aircraft come out on the C.G. properly unless it wasn't build per the manual, i.e. servo, battery, tank placement, etc.

Have a good day.

_____________________________

Rick - Columbus, OH
www.ricktressler.com

(in reply to gsoav8r)
       Post #: 1629

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 2:59:38 PM   
KC36330


 

Posts: 2572
Joined: 4/19/2006
From: Enterprise, AL, USA
Status: offline
quote:

ORIGINAL: k8svrick

................... I think the good thing about these advanced aircraft like the F-16 is that a newbie to RC wouldn't make it their first ship and assume they needed to add 2 oz. of lead to the aft section of the plane.............One should never have to add that much weight to make an aircraft come out on the C.G. properly unless it wasn't build per the manual, i.e. servo, battery, tank placement, etc............


you'd better stick with these 'Advanced' prop jets then, it's quiet common in turbines to add sometimes a pound. i prefer to move equipment but on both my Tam A-4s all the equipment was moved forward at least a foot from the 'per the manual' location as well as sticking the smoke system in the nose which is several ounces of weight 3' ahead of the CG.

(in reply to k8svrick)
       Post #: 1630

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 3:31:09 PM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline 		I don't have a wallet that supports turbines. That's why I bought a propjet.

In my humble opinion, while it may be common to have to add 16 oz of weight to make the CG come out in those planes, it presents the appearance, at least, that something may be lacking in the design/engineering of the plane. I agree that moving the equipment locations around to set the C.G. is the preferred method.

Having said all that, if the kit is intended to accommodate a wide variety of power plants and options, then I can see where a specific configuration of gear would result in a weight and balance issue that would require the addition of stategically placed ballast. Bottom line is, I hate to have to add weight and avoid it whenever possible.

Thanks for the comment.

_____________________________

Rick - Columbus, OH
www.ricktressler.com

(in reply to KC36330)
       Post #: 1631

RE: THE NEW CERMARK F-16 BUILD... - 7/22/2008 3:53:29 PM   
Hot Rod Todd



Posts: 497
Joined: 10/14/2002
From: Cedar Rapids, IA, USA
Status: offline 		If you design a sport plane you can easily make it come out so the equipment makes the CG close to what you need. When making a scale aircraft the original proportions can make the addition of weight neccessary. Some examples include an early model Zero and a Sopwith Pup. There is NO way you will not have to add lead in either of those planes unless you take great liberties in the general layout which will make it look quite un-scale. The F-16 prop jet with its long nose and delta wing is a design that will need tail weight no matter how good you design it. Now, you could move the wing forward and make it look similar to an F-16, but then who would want to buy it? I do not believe it is a bad design just because you have to add some lead. It does not help that we are sticking big .90's on a plane that is basically designed for a .60 (That might be a design error).

All this aside, for a company to make a major change in an aircrafts proportions and not take the time to re-check the CG before putting it out on the market is just crazy. I hate to think how many of these planes may have enjoyed a much longer life span if Cermark would have changed the CG when they put out the new version. If they still have not changed the manual, they are just plain negligent.

(in reply to k8svrick)
       Post #: 1632

RE: THE NEW CERMARK F-16 BUILD... - 7/22/2008 4:22:54 PM   
KC36330


 

Posts: 2572
Joined: 4/19/2006
From: Enterprise, AL, USA
Status: offline 		it's not just adding the 90 it's that the engine is mounted in the nose, that's allot of weight that far in front of the CG. my ducted fan F-16s easily balanced with minimal shifting of the components because the bulk of the engine/pipe/fuel was on the CG. with the turbines you have to put all your batteries/pumps in the nose cone because the bulk of the engine weight is behind the CG. for different sized turbines we offset by putting the lighter turbines in the tail cone without a tail pipe, the overall weight is reduced over the larger turbine in the conventional (conventional for RC, not scale) area using a tail pipe.

(in reply to Hot Rod Todd)
       Post #: 1633

RE: THE NEW CERMARK F-16 BUILD... - 7/22/2008 4:30:20 PM   
Hot Rod Todd



Posts: 497
Joined: 10/14/2002
From: Cedar Rapids, IA, USA
Status: offline 		The fuel tank so far in front of the CG is another problem. If you ever try landing with the tank near full on the Cermark F-16 you will notice it is quite nose heavy. I try to always burn off some fuel before trying a landing. I'm sure the turbine people try to get that heavy fuel load they use as close to the CG as they can.

(in reply to KC36330)
       Post #: 1634

RE: THE NEW CERMARK F-16 BUILD... - 7/22/2008 4:37:43 PM   
KC36330


 

Posts: 2572
Joined: 4/19/2006
From: Enterprise, AL, USA
Status: offline
quote:

ORIGINAL: Hot Rod Todd

I'm sure the turbine people try to get that heavy fuel load they use as close to the CG as they can.


at or slightly in front of but never more then an inch or two, we're hauling 7-10 lbs of fuel and can't afford that much of a shift in CG as it burns off.

(in reply to Hot Rod Todd)
       Post #: 1635

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 7:10:54 PM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline
quote:

ORIGINAL: gsoav8r

Rick,
When you receive your plane, would you be kind enough to tell us all if Cermark has bothered to add an addendum for the CG or update the instructions.
I believe the manual states the CG to be 8.5 inches. But that is wrong and should be 7.5.

Cermark has known about this for at least a year but to my knowledge hasnt addressed the issue.

Thanks,
James


Okay, so the RCU server just had a hissyfit and trashed my post. Here goes again.

Got the F-16p this afternoon just before lunch. All inspected and no damage to report. Everything appears to be accounted for.

Assembly manual - Still shows the CG at 8 1/2" aft of the leading edge at the root. No addendum.

Gear mounts typical of Series 3 kits.

_____________________________

Rick - Columbus, OH
www.ricktressler.com

(in reply to gsoav8r)
       Post #: 1636

RE: THE NEW CERMARK F-16 BUILD ... - 7/22/2008 7:34:16 PM   
miklos



Posts: 195
Joined: 4/1/2004
From: Meriden, CT, USA
Status: offline 		Do yourself a favor and beef up those gear mounts while you can still get at them. Also, loctite all the screws on the retracts. I had a set screw that holds the knuckle pin fall out of one of my retracts and didn't realise it until the pin fell out. The set screw is not visible unless you remove the 2 c clips that hold the piston in place and then it is visible.

(in reply to k8svrick)
       Post #: 1637

RE: THE NEW CERMARK F-16 BUILD... - 7/22/2008 8:20:52 PM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline 		In case anyone's interested, the Rev date on my F-16p assembly manual is 4/06. Additionally, they also discuss the CG range on page 15 as being acceptable from 8 1/2 to 9" which, as has been determined is incorrect.

_____________________________

Rick - Columbus, OH
www.ricktressler.com

(in reply to miklos)
       Post #: 1638

RE: THE NEW CERMARK F-16 BUILD ... - 7/31/2008 12:42:09 AM   
k8svrick


 

Posts: 125
Joined: 3/21/2007
From: Columbus, OH, USA
Status: offline 		Miklos,

Thanks for the tip. I'll be sure to follow up on that one. Whatever I can do to preclude a system failure will make that first, and future flights more enjoyable.

Thanks

_____________________________

Rick - Columbus, OH
www.ricktressler.com