Variable geometry wing models are always fun! The F-14 Tomcat should make for a few interesting variations particularly at this scale.
Twin Motor Cluster for sure are going to be a different challange and will likely have to be handled completely differently then we did with the F-15 Eagle earlier. To be sure After looking further into this models Wide setting motor spacing Ducting to the cockpit core is out. We'll have to resort to an old stand-by "Intake Duct" recovery ejection. Our little model does not offer Intake openings straight from the box we'll have to alter a number of part but the more I look at it the more like it is the only workable solution.
Flight mode for our F-14 will be with the wing in the swept back postions. I'm hoping I will be able to retain the movable pivot option for display but if necessary will fix the wings swept back. our cardboard cutout will reflect this decision. side view didn't make the photo Sorry I'll include it when I do the drawing later.
First tape up with a couple dummy cut pieces of T2+ in the motor openings seem to suggest our idea "could work". Time to start removing interior and exterior plastic to make room for your shockline, motor tubes and ejection ducts.
Alrighty then.
lets remove a bunch of internal plastic. Route, file and sand open our required Intake ducts for some form of streamer recovery.
Twin motor tubes with external Beading wire shockcord anchors and short 90lb kevlar streamer shockline attachment loops are prepaired with 3/16" spent motor casing motor stops glued in standard T2+ tubes.
If I can get these motor mounts installed I think we will be able to proceed with the rest of the build. The Plan is to line the forward exposed plastic areas of the intake with adhesive backed Stainless Steel tape hopefully will absorb most of the momentary ejection heat and after burn.
How are you going to pack all the cord and streamer in that little space without it becoming a tangled mess?
kevin
Kevin:
it's actually not a problem. first remember we are using an external shockcord anchor. Because there is so little room in the motor mount tubes the very short, (6 to 8") streamer is inserted (Talc baby powdered well) creating a loose but sealed plug. then the shockline is tweezered in on top just tightly enough to maintain position. This process works OK on 72nd scale and larger models...this is a first attempt for me at this scale.
One more thing. If we have too much shockline I'll shorten it to fit after the rest of the build is complete. We really only need enough line to keep the streamer from being stripped off as it opens. but it (the streamer) actings as our Wadding Has to completely exit the intake...Which MIGHT be a problem if packed Too tightly. This is why intake ejection systems are LESS reliable then other ducted or noseblow ejection systems.
Last edited by Micromeister; 6th April 2012 at 04:33 PM.
Finished the construction phase on our F14 Tomcat this weekend. Actually did most of the model construction at our monthly Narhams business meeting so I didn't get a lot of the construction photo's I intended.
Basicly one I installed the duct lining Stainless steel tape to help reduce much of the ejection charge heat and afterburn melting of the fuselage plastic the model more or less went together almost instantly.
Satruday morning the Tape folding and installing began. I did get a couple photos of this. Starting with the Upper fuselage coating all the open area head of the motor tubes, the underside of both wing pivot plates and down into the created recesses of each in-take opening. Burnishing down the tape and adding a bit of CA at the ever edges should help with the slide in and out of the 1/4" x 10" green teflon tape streamers and shocklines.
Unfortunately one of the photos that showed the streamer being tucked into the intake was corrupted during transfer I'll try to remember to take another during while finishing the model.
After completeing the build the other corrupted photo showed the model dangling on a kevlar thread with a heap of red clay discs stuck to the nose.
Once we got the clay to have the model hanging at it's projected CG nice and level. The clay was placed in a zeroed empty cup on our gram scale to get the weight. Then we substituded #9 lead shot for the clay at the same 5.2g mass. It's pretty amazing how much space the use of #9 shot saves which also sometimes allows a bit less mass to be needed to get the model balanced. adding a tiny bit of CA followed by a seal of 5minute epoxy our bird is just about ready for primer and paint.
I've found the 2" adhesive backed Stainless steel tape very useful in a number of Mod-Roc applictions. Cluster or booster motor bulkhead coverings, ejection charge mixing chambers in clusters. all kinds of heat reducing applications as with our PMC here. 1st pic below has a couple different metal tapes I've found useful.
After nose weight balancing all that's left are the Launch Lugs...DARN those launch lugs again, our 4 sparrow missiles a clear canopy. those last 5 items well be left off until after primer & painting. Missiles will likely just be hand painted while waiting for the primer to dry. I'll restuff the streamer/shocklines and add a bit of wadding to protect them during painting.
Open the wings to wide Landing configuration, Install a spent motor casing in one tube our handling rod in the other, we'll be ready for primer.
Last edited by Micromeister; 10th April 2012 at 03:26 PM.
Looks like a fun and challenging build. Really tight confines. I noticed your sweep back angle looks like the 75 deg oversweep we used for storage. Honestly for rocketry purposes it's probably better to use that.With the 68 deg angle , the main trailing edge and the elevon leading edge are parallel. I'm just pickin nits--I think it looks great and is a cool build !!
Looks like a fun and challenging build. Really tight confines. I noticed your sweep back angle looks like the 75 deg oversweep we used for storage. Honestly for rocketry purposes it's probably better to use that.With the 68 deg angle , the main trailing edge and the elevon leading edge are parallel. I'm just pickin nits--I think it looks great and is a cool build !!
Have no Idea what the wing swept back angle is.....They are set against the stops.
This little birds wings have I believe 4 tines on the pivot hubs that really don't interlock very closely at all, While the wings don't flop around there really isn't much resistance holding them at any given angle. Sometimes both wings move if the tines engage other time the only half engage leaving one wing off angle. They are loose enough I have considered gluing them permanently in position but that really takes one of the KEWL aspects away from model. I am Hoping primer & Paint will tighten them up a little.
I'll still set flight config in the swept back position with the wings to the stops pretty much as shown. If not; I'm pretty sure they will put themselves there under thrust.
Interesting to know there is a difference between the swept flight and storage angles though. Do or did you work on or fly Tomcats at some point?
Thanks for sharing
Last edited by Micromeister; 10th April 2012 at 03:23 PM.
Flew the A---A+/B--and checked out in the D. Most of my time was in 18's active and reserve though. Managed to get a little stick time in the RF-8 before it was gone. The 75 deg oversweep was used onboard for storage making the tailerons the widest part of the plane. They could then be stowed side by side/nose to tail--saved a few feet. At 68 deg sweep, depending on airspeed and other factors ,small glove vains extended above the intake to help with tail loading. Looked like canards but only moved in or out as needed.Sadly, we retired them. Now only our gooooood friends in Iran fly them. Last time I talked to a buddy of mine they had 20-25 mission capable/rebuilt/refitted
Flew the A---A+/B--and checked out in the D. Most of my time was in 18's active and reserve though. Managed to get a little stick time in the RF-8 before it was gone. The 75 deg oversweep was used onboard for storage making the tailerons the widest part of the plane. They could then be stowed side by side/nose to tail--saved a few feet. At 68 deg sweep, depending on airspeed and other factors ,small glove vains extended above the intake to help with tail loading. Looked like canards but only moved in or out as needed.Sadly, we retired them. Now only our gooooood friends in Iran fly them. Last time I talked to a buddy of mine they had 20-25 mission capable/rebuilt/refitted
Very KEWL stuff, I'm truly envious!
Thank you for all your service. I can only imagin flying fighters for real, did a simulation and prop flights a time or two....Always wanted to fly but was told by our AF recuiter I was too tall, so didn't go in...I kick myself at least once a year LOL!!!
I recently repaired a Grumman Factory gift model of an F-14A Tomcat for a former Grumman employee friend of mine that has the working forward small canards...pretty neat how they extend and retract with the sweep angle of the wings.
Last edited by Micromeister; 11th April 2012 at 02:47 PM.
A Bit more progress on the F-14 Tomcat.
got the bird Primed, sanding and base painted Light Sea Grey. Added Silver, Jet Exhaust and matte black brushed on just for fun. Hoping to get it decaled before this weekends club launch? We'll have to see.
Have to give a small warning to those who purchase LEE plastic models.
This is the third model I've built from this manufacturer. While the models a pretty nice and the scale work average for this scale model, the decal printing or perhaps it's the base paper leave much to be desired. To be honest I'd forgotten how the brittle conditions of the decals previously.
These Decals were just as Nasty. Soaking almost 30 seconds in PLAIN WATER...NO SOAP. and allowing the decal to relax for over a minute they were sometimes ready to slide around on the backing sheet..several where not and still others took a second 10second dipping and another relaxing minute to loosen on the backing sheet. Once the water based glue was finally ready for application, the model body was wet down with a brush and Decal Sol applied to both just before sliding off the backing onto and into postions on the model. With all that preperation many wanted to curl up into a little ball as it slide off the backing sheet. Luckly I didn't do too many of the decals before noticing the problem. Just had to stop application, pull out the Microscale decal film and recoat all the remaining decals before continuing the process. Didn't help the water base glue soaking time but sure made a HUGE difference once they released, No more flaking into dust along the edges on larger areas nor did they try to curl up after application.
Still have a few that were trying to curl before I noticed. I'll have to knock down the raised edges before applying the matte clear overcoat in a couple days.
If you have or buy LEE Plastic models be sure to apply a new coating of UV clear or Microscale decal film before using them.
Lastly: After adding everything including the dual streamers, missiles and canopy this little piggy has some MASS! less motors she weighs in at 22.3grams... UGH! I'm not sure we're gonna have enough power to lift 25.4grams total LOWt. We'll see..i'm looking for ways to lighten the load but not coming Up with much.
Last edited by Micromeister; 25th April 2012 at 06:07 PM.
Well darn!
Looking at my own photo's I just realized I forgot something! Curd,Crud, Curd!
Was supposted to paint the canopy frame before I attached it. DRAT! now it's gonna be alot harder to knife around the bottom edges. OH well, I thought she was done... That'll give me something else to do over the upcoming rainy Saturday.
Edit: Didn't correct the canopy frame yet but did take the vertical fleet photos.
Last edited by Micromeister; 2nd May 2012 at 09:16 PM.
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Originally Posted by kruland
We'll see..i'm looking for ways to lighten the load but not coming Up with much.
