i3dm

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Hey guys,

I had a privelage to test fly the first Cermark F-18P Prop Jet in Israel (belonging to Noam Cohen), and boy is this plane impressive !!

First let me start off by saying that i have vast expirience with the Cermark F-16P Prop jet (especially the one in the pics owned by Zvika Jan), with OS91, Jett91 and Jett91 LX motors, and it is a wonderful practice for turbine jets !

I didnt really know what to expect from the F-18P since the length and span are the same, but wing area is smaller, so i figured a higher wing loading might cause it to land faster etc.

to my suprise, on the test flight, powered by OS91 FX with Jett 91LX muffler and APC 12x8 prop, she leaped to the air witth about 60 feet of runway under her wheels. this hsppaned because the plane was trimmed up a bit and lifted up on its on.

I retracted the wheels, got her trimmed and did some fly bys and some aerobatics and i musy say i am IMPRESSED. she flys like she's on rails (much more stable than the F16's) and has the power to climb vertically endlessly with the OS91 combo - andthis bird is FAST.

Rolls were faster and more axial than the F16 as well.

Landing time ! this is where i was really concerned. to my utmost suprise, with 1 click of throttle she glided stable as a rock (did have to hold quite a lof of up elevator though) - got close to the ground, started feeding more up elevator and landed a perfect 2 wheeler followed by a 30 foot long wheely on just 2 wheels !

We did 5 flights today, getting more and more comfortable to this plane, and all i can say is this is THE best and prettiest prop jet i have ever seen and flown, and we couldnt ask for better results in any manner !! we are psyched and excited about the results being this good !

Cermark - you guys have a winner here !!

PS - the Robart 650 robostrut was used on the nose gear, together with TWIN robart scale wheels, it was a simple mod from the original nose gear, and loos and works (shock absorber) absolutely perfectly scale. i highly recommend it !

I added some pics for your viewing. Courtesy of www.tisanet.co.il

Thanks for reading.

Amir Assal

Today was absolutely incredible!

kmtranmd

My Feedback: (71)

What was your dry weight and CG location on the F18. I have both versions of the F16, and the newer F16 CG was way off. It is at 7.25" from LE instead of 8.5". I wonder if the F18 has same problem.

Amir Assal

No.the CG location on the F18 was correct.

i3dm

My Feedback: (51)

kmtranmd . we found the newer F-16 manual CG is way back and needed to be moved forward by about an inch, similar to your results.

The F18 CG in the manual is 7" and it flys perfect ! flys inverted nearly hands off.

Dig it

My F-16 manual says 9.5 inches from the leading edge. I've got two flights on it and I'll say that it is nice and stable but I had to add 12oz to the tail. This must be the old version?

bevar

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I like the -18...looks like fun.

Where did you get it? The U.S Cermark website does not list it.

Beave

i3dm

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Here it is:

http://www.cermark.net/ComingSoon.php

Its under "Coming Soon" but it is already in fact available.

bevar

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Thanks!

Beave

i3dm

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Im curious.. Has any one of our US friends flown the F-18P as well ?

Blade47

Check this build thread out.

http://www.rcuniverse.com/forum/m_60...tm.htm#6193173

cheers

i3dm

My Feedback: (51)

Guys,

I forgot to mention - in comparison to the F-16, since we used a twin wheel nose gear with shock absorbing robostrut on this plane it is extremely stable on the ground, and doesnt have any of the F16's tendency to side tipping on the ground at all. [8D]

dotdigital

My Feedback: (41)

I am in USA and just built the Cermark F18. Following the 7" C/G point resulted in disaster- as once the bird rotated I knew I was in trouble- classic tail heavy responce - virtually uncontrollable. I have 20+ years pattern flying experience and used every bit of it in my attempt to land... I did a wobbling go round and made a final but about 25' up and 30 yards from the runway I lost it- as the bird became totally uncontrollable once throttled down to land. Nose snapped right off. Bottom line: The 7" C/G is wrong! I am totally surprised to read others have been OK at this C/G. BTW, this plane builds out of the box totally nose heavy with an OS 91FX and demands quite a bit of lead in the tail... but I hit the 7" C/G dead on when balancing... just like they asked for in the manual. Anyway, I have contacted Cermark on this and await a reply. Nice kit- pity I lost it. I believe Cermark will do right and make amends- Steve runs a great operation....

dotdigital

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I would be curious to know if you have followed the Cermark 7" C/G point, how much weight did u have to add to the tail to make it balance??? You say the 7" is on the money but I found it to be too tail heavy here.

i3dm

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dotdigital, What we did was mark 7" on the wing (i didnt do it myself, my buddy and owner of the plane did it, and he said it was just per the manual), and we saw that we had to put his 1650Mah 5 cell Nimh pack ALL the way back to the tail to get her to balance (not a suprise) and she was stll just a tad nose heavy, meaning when we lifted it at the 7" mark the nose would slowly drop down, it was just a tad really.

We kept it this way to the test flight (no lead used!) and she flys like a dream !! something definitely seems wrong if you had to add a lot of lead in the taill how much did you add and which size pack did you use ? and where ?

dotdigital

My Feedback: (41)

I have a 4 cell nicad pack- I didnt locate it ALL the way in the rear of the fuse ( as I like access to it to swap it out) and instead had it mounted on the rear ply plate section. Thus, lead was needed installed in the far tail ( silconed in) . I used about 9 oz to make the bird sit level on the C/G balancer device I always have used -exactly at the 7" mark ( plane sits inverted on the CG balancer device). No fuel of course. Not a tad nose heavy- perfectly level mind u. Bird was unflyable at this setting and resulted in loss- need a new fuse to make a second attempt. I am surprised to hear of your success... What method did you use to balance the plane ( I am guessing you did it by hand) and did you do it w/ plane inverted too? I suppose you choosing to go a tad nose heavy made a critical difference...
Let me know... I am at least thriled 2 hear that once balanced safe the bird flies great... I have the Cermark F16 already too and was anxius to see the F18 characteristics... maybe on the rebuild I ll hit it!

i3dm

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We held it by hand, upright, no fuel, and landing gear out.

It was just a tad nose down at this setting.

xphstos

i just finish flying today the f 18 it fly very good.......i balance it nose havy.............but i did add 3 oz on the left wing for side to side balance

dotdigital

My Feedback: (41)

Today was a good day for two new F-18 Cermark fliers. We both had succesful maiden flights one right after the other. Both planes were set a bit nose heavy and they flew just fine. See the two happy campers in the photo. Video of the Cermark F18 flight to follow... as no one has posted anything on this thread yet video wise. All in all a great flying plane but you need gobs of space on final to slow her down. This plane loves to land HOT and begs for more power than an OS .91 powerplant too...

CrashPro

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wow...they look great dotdigital...looking forward to seeing some video. I ordered mine Monday,..called Cermark today to see when they are going to ship it,..was told they are out of retracts and it will be minimum 30 days before they have them. Ordered .91LX too, will probably have engine before plane.

dotdigital

My Feedback: (41)

u may want to try GRAVES R/C in Orlando- they ususally have stock and ship 2 day air for $25. if u cant wait for Cermark... they are very nice shop... Google them to locate the site. BTW, one word of advice- set up your radio for at least 50% exponentials on ailerons & even rudders - this plane loves to roll and is very sensative... so be careful till you get used to her... I also fly an F16 Cermark and the F18 is a bit more 'hot' in the air. But Cermark did a great 4 for the money.

i3dm

My Feedback: (51)

dotdigital, we fly our F18 with an OS91 \ Jett LX muffler (gold) on APC 12x8 - its amazing - couldnt ask for more power !! unlimitede verticals and she is FAST.

Try this combo - you will be suprised. the stock OS muffler is crap for this plane (in case thats what you have).

CrashPro

My Feedback: (1)

Hi dotdigital
Thanks for the heads up about Graves R/C,...their website showed 1 in stock,...so I placed order.
Also, congrats on your 'second' maiden flight. Did you buy a complete new Hornet or did you rebuild?
What differences did you make in the balancing this time around?

Thanks again

George

funflyerf4

My Feedback: (6)

I have been flying mine at 6" back from the leading edge It could probley go back another 1/4 or so. I ran out of fuel last night and it glided in real nice.

dotdigital

My Feedback: (41)

the second build was from a replacement kit... the method for balance was NOT to balance inverted- just do it the old fashioned way- use your finger tips under the wing where it meets the fuse. I set C/G at 6" and not 7"- did not require any weights in tail ( battery was mounted in rear).