Topic: hawker harrier jump jet ( large size )

Saw Robin's laser in action today, I didn't realise how quick those units are!! Will be good fun getting the time and cracking on with the Harrier, won't be long

Saw Robin's laser in action today, I didn't realise how quick those units are!! Will be good fun getting the time and cracking on with the Harrier, won't be long

Could be a useful person to know

Could be a useful person to know

hi yoyo , i would be happy to help with my laser just give me a shout,
planeking-robin

hi all, just to let you all know i have Ame not sat on my back side with my feet up.
i have bin working hard on moulds, the left hand side is all most ready, i will post
some pic's this coming week.
I AME A BIT UNDECIDED  witch way to go ? do i mould the rudder fin as part
of the fuz  and cast it all in one, or do i make it separate ?.
any suggestions ?.
i wonder if it will be litter cast as one  .
planeking-robin

hi all, just to let you all know i have Ame not sat on my back side with my feet up.
i have bin working hard on moulds, the left hand side is all most ready, i will post
some pic's this coming week.
I AME A BIT UNDECIDED  witch way to go ? do i mould the rudder fin as part
of the fuz  and cast it all in one, or do i make it separate ?.
any suggestions ?.
i wonder if it will be litter cast as one  .
planeking-robin

Having it separate will make it a bit shorter for transport, but then again it's always going to be awkward anyway.

I'd probably go for moulding it in one piece for simplicity, unless that makes the mould a really awkward size or shape.

Having it separate will make it a bit shorter for transport, but then again it's always going to be awkward anyway.

I'd probably go for moulding it in one piece for simplicity, unless that makes the mould a really awkward size or shape.

hi yoyo , thanks for that , i think i will mould it in one , i did think of making the fin in fiberglass then bondding it on
when joining the fuz what do think ? 
planeking-robin

hi yoyo , thanks for that , i think i will mould it in one , i did think of making the fin in fiberglass then bondding it on
when joining the fuz what do think ? 
planeking-robin

I've never done anything like that anyway, so hopefully there are others who will chime in...

If it's separate it becomes another thing to line up when doing the bonding. Unless you mould a socket for it in the two fuse halves so it gets aligned automatically?

Hang on though, didn't you buy the fuse mould anyway? What does it do about the tail already?

I've never done anything like that anyway, so hopefully there are others who will chime in...

If it's separate it becomes another thing to line up when doing the bonding. Unless you mould a socket for it in the two fuse halves so it gets aligned automatically?

Hang on though, didn't you buy the fuse mould anyway? What does it do about the tail already?

hi yoyo,  on the fuz ,the fuz is cut level i can not see how it is fixed yet , it doz not look very strong
there is no lip.
the fin fills a bit flimsy that is whey i though of making it in fiberglass ? .
planeking-robin

hi all, just sume pic's of the left hand side mould as is so far.
just to show i ame still at it not much fun trying to make somthing
of it,in fact i ame starting to get a bit p,off with it ,
3 weeks on this side all ready  never mind must keep it up.
not much longer? on this side
planeking- robin

hi all, forgot to put the pic's on.
planeking-robin

hi all, just sume pic's of the left hand side mould as is so far.
just to show i ame still at it not much fun trying to make somthing
of it,in fact i ame starting to get a bit p,off with it ,
3 weeks on this side all ready  never mind must keep it up.
not much longer? on this side
planeking- robin

Don't fret about it Robin, I've had planes in 'actively being repaired' status for months... life just gets in the way sometimes!

I usually find I keep plodding on then suddenly it all comes together in a rush.

I didn't think the moulds needed that much doing, I thought the main work was in doing those little 'extras' like, ooh, the wings?

hi all, sorry it bin some time but bin busy building a plane for pb models,
and now i Ame back now and will be getting stuck in to the harrier now.
plus i just got a vacuum forming machine today.
i was thinking of vac/forming all the ducting with this machine ?
what do you think yoyo will this be better than fiberglass?
planeking-robin

hi all, sorry it bin some time but bin busy building a plane for pb models,
and now i Ame back now and will be getting stuck in to the harrier now.
plus i just got a vacuum forming machine today.
i was thinking of vac/forming all the ducting with this machine ?
what do you think yoyo will this be better than fiberglass?
planeking-robin

I'm no expert, I'm just noisy!

But... vacforming sounds like it has potential, it's just that most people don't have the facilities.

I always say that no job is worth doing unless it needs a new tool. Sounds like you just got the new tool that this job needs!

Is a vacformed shape that's sturdy enough to handle the vacuum or overpressure in the ducts going to be any lighter than fibreglass? Probably easier to make a former than making a new mould for fibreglass it though.

 

I'm no expert, I'm just noisy!

But... vacforming sounds like it has potential, it's just that most people don't have the facilities.

I always say that no job is worth doing unless it needs a new tool. Sounds like you just got the new tool that this job needs!

Is a vacformed shape that's sturdy enough to handle the vacuum or overpressure in the ducts going to be any lighter than fibreglass? Probably easier to make a former than making a new mould for fibreglass it though.

hi yoyo, i though the same but when the v/f/m came today it had a sample show it can do and it was very solid
as it is only 1mill thick .
planeking-robin

There's a ducted fan video for sale on BMFA that includes footage of ducted fan Harrier, probably Mike Koskela's?

http://www.bmfaclassifieds.co.uk/detail.php?id=81595

There's a ducted fan video for sale on BMFA that includes footage of ducted fan Harrier, probably Mike Koskela's?

http://www.bmfaclassifieds.co.uk/detail.php?id=81595

hi thommo,    many thanks for the info i rang the guy at 9.30  but he has sold it   
once again many thanks.
planeking-robin

hi PDR , i Ame just drawing the wings out on my laser program ready to cut out
and make.
i have got hold of a scale plan for the harrier mks.g.r.1 & t.2 on the plan it shows
slip on ferry tips fitted in place of combat tips to increase the lift and range.
do you think it would be better to make the wings to this size to make it more
stable and more lift +it will make the wing span bigger  
planeking-robin 

Don't bother! In the model size they will make no difference and just look odd. In the full size they were abandonned very early on (I don't think they were ever used operationally) and I don't think the Sea Harrier wasn't even equipped to use them.

PDR

Don't bother! In the model size they will make no difference and just look odd. In the full size they were abandonned very early on (I don't think they were ever used operationally) and I don't think the Sea Harrier wasn't even equipped to use them.

PDR

hi PDR, many thanks for your advice i will take it and forget them .
i have all most done the ribs in dxf for my laser,when i have cut them out i will post them

HI ALL, i have just cut the first set of wing ribs for the harrier on my laser
i may have to alter the first 2 or 3 ribs for the wing braces.
will post the plan of the wing later .
planeking-robin

HI ALL, i have just cut the first set of wing ribs for the harrier on my laser
i may have to alter the first 2 or 3 ribs for the wing braces.
will post the plan of the wing later .
planeking-robin

Looking good. VERY jealous of your array of tools...

Looking good. VERY jealous of your array of tools...

hi YOYO , you will build up your tools as you go along like me as you get older.
if i had kids at home i would not have what i have , but my kid have flown the nest
planeking-robin

hi all , can any body tell me what the andhedral degrees is on the harrier wings
is , as i can not find it any where  i must be looking in the wrong
places.
any ideas PDR if you can get back to me.
just to let you know i Ame just making the wings up and will post pic's tonight.
planeking-robin

12 degrees anhedral for the wing, and 15 degrees anhedral for the tail if I am not mistaken.

12 degrees anhedral for the wing, and 15 degrees anhedral for the tail if I am not mistaken.

hi EREZ , many thanks for the info  .
just to let you all know it is snowing in andover hant's.
planeking-robin

hi all ,as promist some pic's one of the wings not yet finished but getting there.
i have bin looking at some electric retracks for the end of the wings 2.0 kgs
i think will be ok .
has any one used any of these if so are they any good ?.
will post more pic's of the wings as i go a long.
planeking-robin

hi all , i watched a clip on youtube on the harrier at a show when it was in
a hover and it had fall flaps it looked like the ailerons are tilted down a bit
Ame i correct ?.
as i Ame new to ductted fan planes is it best to keep the thrust out lets
big or small for the best power ?
the ones on the plane look bigger than they should be i may be wrong.
any advice is most welcome .
planeking-robin

hi all , i watched a clip on youtube on the harrier at a show when it was in
a hover and it had fall flaps it looked like the ailerons are tilted down a bit
Ame i correct ?.
as i Ame new to ductted fan planes is it best to keep the thrust out lets
big or small for the best power ?
the ones on the plane look bigger than they should be i may be wrong.
any advice is most welcome .
planeking-robin

Would it be worth getting a cheap and tough EDF model first to practice with and use as a testbed?

The FunJet seems to get mentioned a lot...

Would it be worth getting a cheap and tough EDF model first to practice with and use as a testbed?

The FunJet seems to get mentioned a lot...

hi yoyo , i have a grate planes red arrows hawk ,
i ask because i will be starting to get the ductting ready in the week or so ,
and want to try 2 or 3 types to see witch gives the best thrust,and that Wye i asked.
planeking-robin

Generally the closer to 100%FSA the higher the thrust. For your needs I would suggest trying 100% 95% and 90%. To find the compromise where thrust meets your needs and in flight performance is adequate.

hi yoyo , i have a grate planes red arrows hawk ,
i ask because i will be starting to get the ductting ready in the week or so ,
and want to try 2 or 3 types to see witch gives the best thrust,and that Wye i asked.
planeking-robin

I see TSR  has answered, but you may have better luck if you ask in the EDF part of the forum instead of jet turbines?

Generally the closer to 100%FSA the higher the thrust. For your needs I would suggest trying 100% 95% and 90%. To find the compromise where thrust meets your needs and in flight performance is adequate.

hi tsr, thanks for the info.
sorry to be a plank but what is FSA ?, i guess it may be fan size aperture ?
planeking-robin     ps i think i need to get some books on ducted fan's

I see TSR  has answered, but you may have better luck if you ask in the EDF part of the forum instead of jet turbines?

hi yoyo , thank for that i will try that to morrow  .
planeking-robin

Sorry FSA is Fan Swept Area.
(sqrt ((((pi*fan radius^2)-(pi*hub or motor tube radius^2))*90%)/pi)*2)
If you cut and paste the above into Google and substitute the fan and motor tube radius text for the relevant numbers it will give the diameter outlet equivalent to 90% FSA in this case. Get rid of the last pi and 2 to get the area divide that by 2 for a two duct system. 

Ducted fans need laminar flow and do not like changes in cross section as this requires work to be done. However they are happy to have a slight reduction in the efflux diameter for a minimal loss in static thrust.

Most EDF systems for fast jet like flight work well with 100% FSA and an eliptical inlet on the intake. But for your Harrier I would suggest 110% might be better. Whilst the norm for the efflux side is to taper the duct to about 85% FSA. With your Harrier I would look at 95% FSA. The reasons for this are that you need lots of thrust at 0 airspeed.

hi tsr, thanks for the info.
sorry to be a plank but what is FSA ?, i guess it may be fan size aperture ?
planeking-robin     ps i think i need to get some books on ducted fan's

As tsr says the cross sectional area of inlet/outlet ducting is critical to ducted fan performance and needs careful design to maximise thrust.
A good book for you would be Ducted Fans for Model Jets by David James which I believe explains this in some detail:

http://www.amazon.co.uk/Ducted-Fans-Model-David-James/dp/0852429770

http://www.ebay.co.uk/itm/Ducted-Fans-Model-Jets-David-James-/320815558236

http://www.myhobbystore.co.uk/product/17670/ducted-fans-for-model-jets

The same author also published a good book on Ducted Fan engines too:

http://www.amazon.co.uk/Engines-Ducted-Radio-Control-Handbooks/dp/1854860178/ref=sr_1_1?s=books&ie=UTF8&qid=1328954625&sr=1-1

As tsr says the cross sectional area of inlet/outlet ducting is critical to ducted fan performance and needs careful design to maximise thrust.
A good book for you would be Ducted Fans for Model Jets by David James which I believe explains this in some detail:

http://www.amazon.co.uk/Ducted-Fans-Model-David-James/dp/0852429770
hi tsr & thommo , many many many thanks for all the help ,
thommo will go on line see if i can buy the books asp.
once again many thanks  .
planeking-robin

http://www.ebay.co.uk/itm/Ducted-Fans-Model-Jets-David-James-/320815558236

http://www.myhobbystore.co.uk/product/17670/ducted-fans-for-model-jets

The same author also published a good book on Ducted Fan engines too:

http://www.amazon.co.uk/Engines-Ducted-Radio-Control-Handbooks/dp/1854860178/ref=sr_1_1?s=books&ie=UTF8&qid=1328954625&sr=1-1

hi all ,can any one recommend what servo,s to use for the flap,s and ailirons
as i Ame trying to keep it as light as Po's, so small ones i think ? and as is the first jet i will have built want to get it right.
the flap size is 256x50 mm.
the ailirons is 175x50 mm
planeking-robin

HI ALL, JUST SOME PIC'S of the wing as is with the retract servo in position
i Ame going to use get some hitek hs125 mg for the ailirons.
planeking-robin

HI ALL, JUST SOME PIC'S of the wing as is with the retract servo in position
i Ame going to use get some hitek hs125 mg for the ailirons.
planeking-robin

for got the pic's
planeking-robin

Spot on mate! I'll have to pop over on the weekend ;-)