150% Twin EDF F-15 Eagle built

[ER69]

Hi guys,

I was thinking of wat to built for my next project during the past few days, as my on going SU27 project is coming to the ending part.
I want to built something huge and different which i never flew before.
Anyway, I got inspired by Mr. Harald Huf on his very scale and really huge Turbine SU27. Therefore, I decided to build a up scale 150% F15 out of depron and balsa as my next project.
With the technology of the lipo and BL motors nowadays, I think that it should'nt be much a problem to power up this size of Jet by EDF.
Before I go any futher, here are the specs & electronics which I am planning to use on this Twin EDF Jet.

Length : 1.6m
Wingspan : 1.06m
Wingarea : 578sq.in
DF unit : 2 X Wemotec fan
Motor : 2X HET 2w20 (700watts)
ESC : 2 X 60 or 80A
Batt : 4 X 4s1800mah (20C)
Amp draw : Roughly around 45~50A (To be tested)
Watts : Roughly around 1300~1400watts
Landing gear : Micro air retracts
Lighting : Full navigation
Fully Glassed

This EDF Jet will finish out around 1.8~2kg depending on the electronics and batts that i had decided to put in end of the day.
So with such weight, I will only need around 600~700 watts of power output to fly this baby.

Due to the size of the fuselage and wings, I have to splice foams together on them when building.
Anyway, This is my first time building such a "Huge" EDF Jet, so I really appreciate builders who had experiences on building huge stuffs or jets to contribute their ideas and advices if you think something is wrong or missing as it goes along.
Well, I shall talk no more, here are some pictures of the Plan being pasted on deprons waiting to be cutted out and how the jet will looks like when finished.

[ER69]

Due to it size, I bet lots of sanding jobs are to be done and i think i will be covered by tons of foam dust at the end of the day.
I really dont wish my right arm to be more muscular than my left arm after this project.
Anyone can recon me on sanding machine which is compact and easy to use. Appreciate if you can also tell me where can i get them.
Thanks

[ER69]

Little history of the F15 Eagle

For those who wan to know more about the F15, here is a little history of it.

The McDonnell Douglas F-15 Eagle is today one of the world's most formidable interceptor fighters.
Although largely designed in the late 1960s and early 1970s, it still remains the primary air-superiority fighter serving with the USAF, and will remain so well into the first decade of the 21st century.
In service with the United States, Israeli, and Saudi Arabian air forces, the Eagle has scored an impressive number of air-to-air kills, perhaps approaching 100, with NO known air-to-air losses.

The McDonnell Douglas F-15 Eagle has its origin back in the mid-1960s, when the US aircraft industry was invited to study US Air Force requirements for an advanced tactical fighter that would replace the F-4 Phantom as the primary fighter aircraft in service with the USAF. Such an aircraft needed to be capable of establishing air superiority against any projected threats in the post-1975 period. Without compromising the primary air-to-air combat role, the aircraft was to be capable of performing a secondary air-to-ground mission.

Throughout much of the Vietnam War, the primary fighter in service with the USAF was the McDonnell F-4 Phantom, a large, twin-engined, two-seat aircraft. The Phantom had originally been designed back in the 1950s to Navy requirements for a two-seat multi-role fighter, intended to destroy enemy aircraft at beyond-visual-range (BVR), using a powerful fire control radar to detect threats and to direct Sparrow semi-active radar guided missiles against them. No cannon was provided, since the received wisdom of the late 1950s was that the internal gun was an obsolete holdover from the pre-missile age. However, the North Vietnamese air force was equipped with MiG-17s and MiG-21s, small, relatively unsophisticated aircraft designed for close-in dogfighting. In the years 1965-68, the kill-ratio in air battles against the North Vietnamese Air Force was only 1.5 to one, much poorer results that those obtained in Korea by the F-86 Sabre against the MiG-15. One of the reasons for this rather poor record was the rather restrictive rules of engagement over North Vietnam, which required a close-in positive identification of the enemy before missiles could be fired, negating the advantage of the Phantom's powerful radar and long-range Sparrow missiles. In a close-in knife fight against MiG-17s and MiG-21s, the Phantom was considerably less maneuverable and was at a relative disadvantage in these types of encounters. Another reason was the fact that most USAF pilots had never been trained for air-to-air combat, and did not know how to exploit the strengths of their own aircraft against the weaknesses of the enemy's planes.

As a result of the experience over North Vietnam, the Air Force concluded that they had better pay more attention to the possibility of close-in air-to-air fighting in the design of their future fighter aircraft, and not simply rely on superior radars and long-range missiles to ensure victory. At first, the Air Force was rather uncertain of just what kind of aircraft they wanted to replace the Phantom, and their initial requests for proposals were rather vague and tentative, relying more on the industry telling them what they should be buying rather than issuing any specific requirements.

No wonder RSAF is replacing our fighter Jet with this.

[Shark]

[$h@d0w]

Due to it size, I bet lots of sanding jobs are to be done and i think i will be covered by tons of foam dust at the end of the day.

Wear a mask man. Don't breath in too much of those things.

[Fn5s]

Hi,

Kinda interested to know if foam is lighter or fibre is lighter...

Cheers.

[ER69]

Hi,

Kinda interested to know if foam is lighter or fibre is lighter...

Cheers.

Hi Fn5s,
Well, It all depends on wat type of foam and the weight of the glass cloth used to make the fibre glass.
but i can say that fibre is "stronger & harder" than foam.
Foam can be too, if you glass it.

[AsiaSRC]

jet size "appetite" is increasing lately, welcome to GIANT scale world.

1.6m in LEN seem a bit "stressful" for edf to push around? I've no experience on this, and probably my feeling is acting on behalf.
Or i'm the only person still talking Nicd in Lipo era..

I flew the 2m bigger bro. and think that F15 is a "dragging dog" and if a low power to weight ratio is adopted, definitely wont you get too far. But once you "burn" this eagle habit in yr brain, man! you going to love this plane as long as you live. Of course, in "sucker" world.

Next concern is the plane shape (catchment area), yr edf thrust push it ard is necessary especially banking into wind or tracking at crosswind..

Also need some brainstorming since weight is biggest barrier for a robust stuctures design too, plane of this size can generate G-spots as you get foldup up there.

Neither, still worth a try, and always open my mouth for u if need me to kipo !

[jameswilliam]

Ernest bro,

Since you 're doind a big scale F-15 Eagle with foam just to check why not get those bigger foam from Artfriend foam? The one we used to get is those 3ft x 2ft right why not get those more bigger one I believe you saw it before right?. And about the sanding if the foam is in 5mm and need to sand it into round area to a 150% scale the round area might looks a bit too small so you might want to thicker the foam to 10mm in some area for sanding down to rounding area. BTW, ESC80 will be a better choice to choose.

Jameswilliam

[ER69]

jet size "appetite" is increasing lately, welcome to GIANT scale world.

1.6m in LEN seem a bit "stressful" for edf to push around? I've no experience on this, and probably my feeling is acting on behalf.
Or i'm the only person still talking Nicd in Lipo era..

I flew the 2m bigger bro. and think that F15 is a "dragging dog" and if a low power to weight ratio is adopted, definitely wont you get too far. But once you "burn" this eagle habit in yr brain, man! you going to love this plane as long as you live. Of course, in "sucker" world.

Next concern is the plane shape (catchment area), yr edf thrust push it ard is necessary especially banking into wind or tracking at crosswind..

Also need some brainstorming since weight is biggest barrier for a robust stuctures design too, plane of this size can generate G-spots as you get foldup up there.

Neither, still worth a try, and always open my mouth for u if need me to kipo !

Thanks alot for those advice
I will keep the weight down and give more thrust to it.
I am planning to play with higer voltage lipos. ( 4~5s)
and I am talking about 1200~1400watts on 1.5~2kg Depron Jet.
I will definitely need your advise on the "How to" install air retracts, as this is my first time using those air operated thingy. anyway, there is always a first time..
Cheers

[ER69]

Ernest bro,

Since you 're doind a big scale F-15 Eagle with foam just to check why not get those bigger foam from Artfriend foam? The one we used to get is those 3ft x 2ft right why not get those more bigger one I believe you saw it before right?. And about the sanding if the foam is in 5mm and need to sand it into round area to a 150% scale the round area might looks a bit too small so you might want to thicker the foam to 10mm in some area for sanding down to rounding area. BTW, ESC80 will be a better choice to choose.

Jameswilliam

I didnt use those 3ft x 2ft depron coz it only comes in 5mm thickness.
Those i am using now are in 6mm.
As for those round area.., stay tuned and you will find out..

[ER69]

Anyone out there interested in building a scale EDF Jet?
Attached are some pics of F15 and F14 .
Well, Make your dreams come ture, nothing is impossible...
I had almost finish cutting out those depron for my 150% F15 and
Will starts posting once i starts building it..
Cheers...

[ER69]

General Construction Notes.

Hi guys,
I am posting this coz i relised that there are getting more & more flyers who had started to scratch build their plane nowadays..

Lots of people had asked me " Ernest, why dont you just get an ARF kit and fly? why waste so much time to build one? "
Well, the answer is :" Coz No one sells those planes that I had built in LHS or if they do, they are very expensive.. futher more its a hobby and i dont think is wasting my time.."
One thing about scratch build is that you can built wat ever size you wan to suit your power plant set up.

For those who had scratch built their planes will know the kind of feeling when you are flying it compare to ARF, the feeling is totally different ..If you dont think so , you guys can ask DH members like " Astroboy", "Stuka", "DennisP" and other builders and I bet they will tell you almost the same stuff...

I had a small talk with some of my flying buddies last week, we had relised that members here are too shy to post their project. Well, its not about "showing off" your project but we think its more about sharing your expriences to others so that they will not repeat the same mistake which you did before..
So guys dont be shy .. Just do it...
Lets make this forum a place to learn and exchange ideas rather than just a forum to answer question like " Where to buy this and that" agree?
Ofcouse, there are lots of very good threads here in this fourm as well.

Well, I think i had been talking alot, anyway lets get the stuff rolling....

First of all, materials use : depron (6mm & 3mm) / balsa / carbon rods / steel rod / glass cloth (3/4oz)

For joining those depron, different situations call for different adhesives, and this model is best using the following types :-

- Epoxy (both 5 and 30 mins)
- Foam-safe CA (with accelerator)
- Contact glue such as GWS (if you have some left over from the kit) UHU Por or UHU
- 3M 77 Spray adhesive

All items mentioned above can be found locally, at either bookstore or LHS.

[ER69]

Forward Fuselage

Begin by assembling the forward Fuse.
I had lay two fuse sides down flat on the work bench (My table is a little small for this Jet that i am building)

Glue the triangle balsa to the location shown. After its dried, glue the 3 bulkheads to either one side of the fuslage.
I am using the GWS glue for this step. You can use foam CA as it will cure faster..

Hehe.. this is where i had stopped last nite...

Well, to be continued..............................

[ER69]

Forward Fuselage

Glue together both side of the forward fuse with GWS Glue.., make sure they are parallel to each other.
While waiting for the glue to dry, I had took some pictures of it, to give you guys an idea how big this F15 is
This is just the forward fuse without the aft fuse and it's almost the same size as the HET F18..
Check it out..