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Yellow F-18 twin weight

Old 03-06-2003, 12:25 AM
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mr_matt
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Default Yellow F-18 twin weight

Does anyone know first hand the flying weight (dry) of a yellow F-18 twin, equipped with either 1 or 2 turbines?

Thanks,
Old 03-06-2003, 03:05 AM
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patf
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Default Yellow F-18 twin weight

matt,

since no one else has chipped in, I seem to remember the guys who did the -18's with a single pegasus power talking about 38 pounds for theirs.
Old 03-06-2003, 03:22 AM
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mr_matt
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Default Thanks Pat

I was hoping the twins can come in at about 42.

So if a single is 38, I can't see how a twin will make 42.

This REALLY sucks.....
Old 03-06-2003, 03:25 AM
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diceman
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Default F18

The single versions are coming in around 36 - 38 lbs dry. Depends on how far forward you can get the engine and weather or not you counter balance the stabs.

Most of the twins are in at around 44 - 47 lbs. dry.
Old 03-06-2003, 04:32 AM
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Joe McBride
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Default Fat albert

Matt,

Mine came in at 41lbs dry and 50 at TO with 165oz of fuel.

Granted mine is so overbuilt it is ridiculous! When I started building mine for an Olympus 4 years ago it was all an unkown and everyone told me the plane would disintegrate (including some of the jet buisness heavies).

I reinforced the fuse heavily with honeycomb matt and fiberglass. The wings has massive aluminum spars that go way out the span (not stock) and 6oz of fiberglass cloth (they are not removable). The stabs are counterbalanced with about 1/2 lb of lead (total) and I needed 2 lbs of lead in the nose to balance because the engine sits too far back with an old bypass. I have a functioning, hydraulically dampened trailing link on the mains with a 2 oz hopper tank of antifreeze in between the inlets. On top of all of this I used 1 gallon of polyester primer (yes you read right) and didn't sand nearly enough of this off!

Anyway, with over 70 flights now I can say the plane is a pleasure to fly. It seems to scoot along with the Olympus once its on the step and it has descent verticle. THe advanced design of the wing handles the weight/wing loading superbly. It will sink at a high angle of attach without a hint of dropping a tip. To see it displace AOA (skid) at the bottom of a loop is a sight to behold. It is very predictable and fun to set in the landing pattern with all the drag of gear and full flaps out, holding half throttle and as she crossed the threshold holding her nose high, cut the throttle to 1/4 and let her sink to the tarmac. Then pull her back to idle and apply brakes.

Rumour has it that the pink AMT hornet weighed 62 lbs at takeoff and Charles (owner of Yellow) had me in stitches one day telling me about a guy who flew one that weighed 72lbs at TO. He told me the guy had a deadstick--"Did it glide?", I asked. He said "yeah, like a fishing weight."

Anyway, aerodynamically, that wing will handle all the weight you want to throw on it and when you put your P160 or two in there she will be a rocket!

Here are some links for stills and vid of mine:

www.joemcbride.com/rcvids
www.joemcbride.com/rcpics

look for the F18 links near bottom for video
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Old 03-06-2003, 05:17 AM
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jetpilot
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Default twin

What about a couple of those P70's. You would have to be saving a ton of weight.
Scott
Old 03-06-2003, 01:14 PM
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Blueskies21
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Default Twin F18

I picked up 1 last month in a trade that is 90% complete..this baby is to die for,the pics you see around do it no justice ,sitting on the gear in front of you this is a tremendous monster ,and the scale gear is amazing to say the least,they couldnt have duplicated it any better I feel.I cycled mine yesterday for the first time.I have some reshaping to do with a heatgun on the gear doors,there is so many on this baby & they lost their fit after awhile from sitting in the guys attic.But when that gear goes thru its cycle it is sweeettt,esp the nose.I just bought a full body blue angel pilot from bluebox & the fully painted cockpit from killer cockpits.I will be using operational canopy ,tailhook & speedbrake(for static display)

I am painting mine up in #5 blue angel,along with wing drop tanks,I will post pics in a month or so when mines RTF..Shes sitting in primer right now with very few things left to do,good thing the flying stabs are removeable too,they are as big as my YA F16's wings!!Anyways I have gotten off the thread topic a bit ,I am flying mine this year with DF powerplants then will convert to a big single next year (a P160 I think or AMT) I dont have my turbine waiver yet.I havent weighed mine as of yet,it has everything in it except powerplants/cockpit ,it feels like approx. 18-20Lbs to me



Steve
Old 03-06-2003, 02:59 PM
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ghost_rider
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Default Yellow F-18 twin weight

My Y/A F-18 with 2 X P-120 weighs 42 lb dry. If you have more questions, do not hesitate to send me a PM.

Regards

Ben
Old 03-06-2003, 03:08 PM
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mr_matt
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Default Hi Gimpy

Originally posted by AAAA


Anyway, aerodynamically, that wing will handle all the weight you want to throw on it and when you put your P160 or two in there she will be a rocket!
Thanks for the info, Joe. I heard the big pink one (?) is even much heavier than yours, and it flies great.

THe single configuration (in my case with a P-200) looks very good and was my plan until the rules change allowing 70 pounds thrust with a twin!

I am getting some good feedback, thanks again
Old 03-06-2003, 04:07 PM
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kevinthoele
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Default Weight on F-18

I have flown mine on both twin AT 180's and most resently converted to one Olympus. The weight of the twin can be done in the 43lb area dry. Adding 200 ounces of fuel will get the weight up there in a hurry. It comes in around 38-39 with the Olympus. Both fly well, but I personally would give the edge to the single engine.

Also balance slightly nose heavy. It seems to land much more gently and not as pitch senitive that way.

Any other questions, just let me know. You will love the way it flys.

Thanks,
Kevin
Old 06-23-2020, 07:46 AM
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Auburn02
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Bumping a super old thread, just grasping at straws at this point but if there is anyone around here still flying (or building/having built) this bird, I'm curious exactly where the weight usually stacks up in the build? I have a completed older style kit (formers originally cut for twin DF) with a single Rhino SE, and I'll be damned if the thing isn't every bit of 46.5lbs DRY. I just can't figure out where it's hiding 10lbs of extra weight if others were able to get theirs in the 36-38 range. This one was built into a D model with an extra cockpit but I can't imagine that amounts for more than a couple lbs. Plus that's all on the nose, and even at 46.5lbs it's teetering on the verge of tail heavy and needing a few ounces more nose weight even!

Saw one comment about if the stabs were balanced, that I'm not sure of but I suppose I could pull mine and weigh them individually - though even if that is the case not much to be done about it now. Other than that I have to assume the weight is in the glassing/priming/painting of the thing, after all the finish on it is so damn thick there's not a single panel line visible. But still - 10lbs worth!?

Anyway I know it will fly at this weight, just trying to save anything anywhere I can, if I can. I'm still half convinced there's a 5lb brick hidden and I just haven't found it yet.

Last edited by Auburn02; 06-23-2020 at 12:21 PM.
Old 06-23-2020, 12:37 PM
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I have done four off them and none got to 46,5 Twin single in high 30's to low 40's
Old 06-23-2020, 01:18 PM
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That definitely fits everything I've read, which is why I'm having such a hard time figuring out why this one is such a pig!
Old 06-23-2020, 06:43 PM
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Auburn02
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Well, while combing through the manual and associated pics comparing structure to mine, today I learned the tail section/tailcones were not intended to be removable. My entire tailcone comes off behind the stabs, and the joint where it bolts back on is beefy as hell. So that explains some of it at least.
Old 06-24-2020, 03:04 AM
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SkyKnight
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I have the twin ARF equipped with JetCat P130s. It is weighing in at 44# dry.
Old 06-24-2020, 07:59 AM
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Auburn02
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Wow, that is a lot of horsepower in that airplane!

I drilled some lightening holes in some of the rear tailcone structure and formers (NOT the stab formers, just in the tail cones) and removed some old tubing/wiring/aluminum tape while I had the pipe out, and moved the retract air tank from behind the rear main former and placed it in the nose of the plane, should at the very least alleviate any need to add nose weight, and if I shed 1/4 or 1/2 lb it's a win-win. But I have to accept that there's no way this airplane will ever weigh under 40...or 42...or even 44.
Old 06-24-2020, 11:59 AM
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smchale
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Any little bit can't hurt. Post pics. i've been working on my twin off and on for an eternity. set up for K100's but that was before the 120 was released in the same can size. by the time i'm finished and ready for them kingtech will have figured out how to put a 160 in that size can. lol.
Anyways, love seeing pics of the yellow twin builds for ideas, etc. so feel free to post away!
Old 06-26-2020, 10:17 AM
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Auburn02
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Well the reassembled weight came in at 46.2, but at least the balance is dead on with no added weight. Maybe should go back to one of the ongoing build threads to add pics, but I'm feeling lazy so here you go Sean.


Removable nosecone.



Obviously this conversion w/second cockpit has to account for a couple of pounds.



You can see the seam here where the tailcones were made removeable. Also has the metal (Tams?) turkey feathers. The removed tailcones and associated structure weighs about 12.2 oz.



Back side shot to show some of the extra structure of the removable tailcones.



Plane already had no speed brake panel, but I also removed the actuator and associated wiring in an attempt to save weight. Can always add it back.



The Rhino could probably stand to be further forward for weight distribution, but then would have too much engine to pipe gap.





Working forward, have the UAT and BVM E-brake above the tanks just forward of main spar.



Tanks (unsure which ones), steering servo (was upright, after I flipped it inverted all of my steering cable alignment woes went away).



Xicoy failsafe/sequencer, Jet Central powerpack, PB Competition SRS, IGyro SRS. No GPS currently, may add one just for grins.



Plane had an Airpower all in one air unit but was giving me fits, replaced with two Xicoy V2 valves and the Xicoy sequencer, much more confidence and saved weight.



Has the SDCrashmaster (sorry I can't recall his name) gear mods, although not in the best shape due to a few landing mishaps over its lifetime. ~1/4-3/8" spacers installed above the top spring to alleviate the tire colliding with the gear door.



Old 06-29-2020, 07:12 PM
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Originally Posted by kevinthoele View Post
I have done four off them and none got to 46,5 Twin single in high 30's to low 40's
I have one of the factory-built ARFs in the Tiger Meet scheme (a work of art really!) .. had it for many years .. a bit of a hanger queen I am ashmed to say! It is 42# dry, powered by a Merlin 200XBL (I measured mine at 180-185, not 200). Flies fine. Mine is on the heavy side with lights, cockpit, etc. Has the Gary M. 100oz tanks for a total capy of 200oz. The kit is the version that came with the CF-sandwiched formers to be stronger for turbine power. I know lots of guys get them under 40 as quoted above. Wish I had done that on mine! But it flies fine..

With the new very powerful and small diameter turbines (e.g. jetcat 100/130) it would be very practical as a twin. When I got mine I wanted to do it as a twin, at the time it would have been 2x120s. As you read above, it is possible but I was afraid it would be too heavy, need to much fuel, etc and chose a single. Starting over today I think a twin would be an excellent choice with today's engines. I have an unbuilt kit that I will do someday as a light-as-I-can-get-it twin...

BTW, if the factory foam wheels are not your cup of tea, the BVM F4 main wheels fit very well and are only slightly smaller dia ... not perfect scale appearance but a really nice wheel/tire combo.

Dave McQ

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