Clausxpf...

do you know how much the FSA of the Stumax fan is???
Just be sure to consider that the diameter of the motor inside is quite big and that area has to be deducted from the fan diameter!

Another curiosity I also have is, how can you state how much the catch area is? If using autocad or similar programs you should have a part of the model shown in the picture to be taken as a reference of know dimension I guess!


Gianluca

Originally Posted by felix72

do you know how much the FSA of the Stumax fan is???

74 sq/cm

Originally Posted by clausxpf

Madmax.
i have traced the photo and got and area of 5165 mm2 as catch area.
that is fine for a 90 mm fan and only 70% of the Stumax SM110..FSA.
it will fly with a duct in it but it will not shine.
Claus

That's a bit more FSA on the inlet than I have on my BVM Sabre, I measured it to be 67%, but it has a nice and gradual change in area all the way up to the fan where it finally reaches full diameter. I'm using a Stumax fan in my plane btw. What I did not expect was that the amp draw installed would be so high, I'm at 100A and close to 4Kw static and this on 11S, so I'm wondering what that will end up being once I get the damn plane finished and flying.

This model has also been flown by many using the original BVM fan and also with a DS-94, both fans having a higher FSA than the Stumax and they do work very well so I would not be too bothered about the intake size on your bird.

felix
FSA for sm 110-56 is according to stumax 7380 mm2
Claus

WW:I have a BVM noseleg unit from an F16, cant see how its a rotating one but I assume it must be?

Where did you disappear to WW? Good to have you back and I like the T-shirt by the way....thanks. As for the nosegear thank you , thank you.....I will PM my address.

[lavamig :
I]thanks for the quick response: what inlets are you using on your F8? did dennis make them?[/I]

No intakes for this plane as it used the Byron fan with the louvers cut out. Maybe Dennis could furnish one....I will ask him.

Fleix72:
the attachment method of the nose gear look weak to me!

The nose blocks are epoxied into the fuselage but you are right and I may install a half former at the nose retract. Actually my Byron F-86 had much the same setup for the nose gear and I never broke it even on hard landings.....so it may be o.k.

Claus:
i have traced the photo and got and area of 5165 mm2 as catch area.

Thanks Claus. I have to say this FSA is new to me as none of the EDFs I have owned had intake tubes installed. When I did the measurement of the intake, the vertical measurement was a guess-a-met because of the nose cone.

There is a build thread somewhere that has this plane using a turbine .






I will begin on the mods to the canopy. The instructions say use screws to hold the canopy in plane but I will be using BVM canopy hooks.

According to an earlier PM from Stu he said I needed @ least 90% FSA for the Stumax to work.

Let me explaine the measurement I did on the intake. The horizonal measurement was measure from the middle and is 104mm. On the measurement for the vertical the measurement is 58mm from the bottom of the intake to bottom of the nose cone. I wasn't sure how to measure the areas on each side of the nose cone so I just did a guess and added 2mm which is the 60mm measurement I gave. So if you guys are right the intake is only 70% FSA which is not enough

By the way I managed to pickup another Crusader kit. It had been started to build and I will keep it as a later build. Two kits and no money....

Well discussing this plane with a couple fellow EDF flyers and we came to the conclusion that the Stumax won't work on this plane. Just not enought intake to supply the air for the 90% FSA which the Stumax needs.

SO....back up an punt.

I have a brand new Byron fan here and XPS will soon have their hog of a outrunner ready to go on sale. Looks like I will go to the Byron fan. I will simply open up the louvers which will supply air to the fan and go. I won't have the big hole (ala Byron) in the bottom just the open louvers which were part of the real F-8. If the XPS motor is all they claim then I should have a plane which not only has plenty of thrust but should fly quite fast too. I also have one of the Hurricane fans which is a replacement fan (with more blades)for the Byron. I have used it on the Byron powered F-86 I buildt last year.....might go good with the XPS motor. I understand Robert @ EJF will have the mounting hardware for the XPS motor mating to the Byron fan......I have another project which will love the Stumax so no big deal.

At any rate I am working on parts and pieces which have nothing to do with the power unit so I have time to think about the whole deal.

If my weight machine is correct here are the dry weights of the F-8

Fuselage - 3lb 12 oz
Wings cores with aelirons -1 lb 8 oz
All other wood, elevator, stab, rudder ect ect. - 2 lb 14 oz.

8 pounds....2 oz


This is one LOOOONG fuselage.

Madmax,

sorry to hear that the Stumax fan is probably not working in the model!!!
The only idea I have on how to exactly calculate the area is to use a program like Autocad and let it do it, but look like it's already been done!
Wish you luck with the Byron/Screamer combination!

Gianluca

I still think the Stumax fan will work fine in that plane, even though the inlet is a bit small. Most scale jets are this way, and they still take to the skies, as already mentioned the BVM Sabre is even worse with a Stumax, and that fan is smaller than the Viofan which is a proven performer in the airframe. And what about many of the JHH or for that matter Yellow Aircraft planes, like their A-4 or F-16? The JHH A-7 as an example has about 60% FSA inlet for the E-Turbax but it still goes 150-160mph on a 12S setup. As long as the design of the duct is nice and clean, I'm sure it will do better than a hacked up plane with a Byron fan. Sure it will be down a bit on static thrust, but once airborne it will come alive, unlike the Byron fan setup which is all about static thrust/low speed.

I will think about the power system for awhile.....right now I am working on mods on the canopy and such. Either way the plane will fly and I will enjoy it no matter. ...or in fact I might just built the Gunfighter and put it on my fireplace mantle...heh! heh!(no way)

Thanks for your input.

Originally Posted by Madmax1965

Well discussing this plane with a couple fellow EDF flyers and we came to the conclusion that the Stumax won't work on this plane. Just not enought intake to supply the air for the 90% FSA which the Stumax needs.

SO....back up an punt.

I have a brand new Byron fan here and XPS will soon have their hog of a outrunner ready to go on sale. Looks like I will go to the Byron fan. I will simply open up the louvers which will supply air to the fan and go. I won't have the big hole (ala Byron) in the bottom just the open louvers which were part of the real F-8. If the XPS motor is all they claim then I should have a plane which not only has plenty of thrust but should fly quite fast too. I also have one of the Hurricane fans which is a replacement fan (with more blades)for the Byron. I have used it on the Byron powered F-86 I buildt last year.....might go good with the XPS motor. I understand Robert @ EJF will have the mounting hardware for the XPS motor mating to the Byron fan......I have another project which will love the Stumax so no big deal.

At any rate I am working on parts and pieces which have nothing to do with the power unit so I have time to think about the whole deal.

I've just seen this thread, having been up in the mountains in China for the last few days (now there's an unusual place!). I'm a little confused why, if the SM110-52 won't work, your EDF friends think a larger fan like a Byron or Dynamax will? What's the reasoning? I obviously don't have access to CAD right now, so I can't do the measurement myself. Claus, did you measure it as the catchment area defined by the stagnation point? A mm or so either way can make quite a difference. Max, could you post another photo with a 6" rule exactly at the front edge of the inlet? This will give us a true scale to work off. If the inlet does end up being too small, I'd stay with the SM110-52 and add a large radiussed lip to the fan, perhaps with a 6" long straight duct as well to smooth the air out a bit before it enters the fan.

Stu.

I have been waiting for you to chime in Stu..........(China huh? Fasinating country that).
Actually the Byron works because you open up the (cheater holes)louvers in the top of the wing. This plane was designed for a Byron. BUT I want to use the Stumax. The 6" straight duct sound good if nothing else. I will do a photo for you sometime today.

Stu i did it fast but as close to the middle i could.

Stu,

What do you think of vortex generators (inside the inlet) for planes with inlets like this? It may keep the divergent duct from flow separation. They'd have to be close to the inlet lip, but I bet there's a chance it could help.

I'd be very surprised if an inlet less than 90% could not be made to work well enough on your fan.

Steve C