I had to remove a ton of ducting to be able to get my Vasa Fan 120 into my Skymaster electric F-18. The Vasa came with an inlet lip (non removable). My question is what happens if I don't seal up the ducting on the front of the fan with the lip? Obviously I will install the proper exit ducting as was supplied. Will I lose thrust? Fill me in.

Have you got a photo of it? The 120's on there site don't show lips?

Vasafan 120
http://vasamodel.cz/img/rotor120/r120_09_800.jpg

http://vasamodel.cz/img/rotor120/r120_09_800.jpg

The lip is no problem for ducting. Jepe had a lip built in to his fan and the ducting just slipped inside of it so it's like it's not even there. He had a ring of epoxy/micro around the duct that seated against the curved lip.

Ok thanks. And what happens if I leave the ducting off? Do I lose thrust or will I be slower?

Originally Posted by CoolerByTheLake

Have you got a photo of it? The 120's on there site don't show lips?

Vasafan 120
http://vasamodel.cz/img/rotor120/r120_09_800.jpg

http://vasamodel.cz/img/rotor120/r120_09_800.jpg

I requested the lip when I ordered the fan but I had no idea it would be put on permanently. I don't want to cut it off.

Roger McCormick, did something about open and closed intake setups in the April/May 2012 issue of RCJI (RC Jet International) mag. Each method has strengths and weaknesses.

I would say give it a try just make sure EVERYTHING inside the fuselage is secure

BTW...I really like those retracts!

an installed thrust test is cheap fast and easy....

Put a scale against the wall with some foam for the nose tip and give it a run up...

Let us know, I've ran with and without ducting and can't really tell the difference

regards

Generally speaking, yes ducting helps.

These are not turbines.

The Ducting is one of the components of maximizing eDF performance. Especially when the model begins to gain speed.


I have a vid (page 24) of my F-104 test flight with the most crude, non ducted flight. It worked but really not nearly to its speed potential.

Also, note that a clean ducted edf installation will perform better that an over amp'ed/watts poorly configured flow air flow system.

The next 104 flight will be same fan, full clean flowing air to the fan.

so has any one did a before and after test with mesurable results?

I know its better to have ducts but Im converting a nitro jet and it has little scale ducts then it opens up with a cheater hole in the bottom. I would like some more info on this. I made the biggest fan lip I could to help it out.

There are plenty of jets that have flown with no ducting, but performance is never really great. They seem to have lots of static thrust, but as soon as they get flying it goes down hill fast. I've never seen a fast EDF with no inlet ducting.

The Eflite Hawk has flown both ways and it has small inlets. The top speed is probably 30% higher with it, so it can be flown with less throttle or just faster and with much more climb rate.

Inlet ducts can be a challenge if they are on the small side. It sure is a lot easier not to do it, but I feel the reward in performance is well worth the effort.

Steve is dead on with my results in my Jet Legend Hawk

I flew the plane with the DS-94 HST with just a lip on the fan...8" clear in front of the fan with the stock duct cut off (14s 6500 mah)

Then flew it with the Dynamax with full ducting from Tam... I also shed 2 pounds so that has to be factored in both at nearly 6000 watts (12s 6500)

Also flew a Cermark F-16 with a DS-96 HDT on 12s 5000 mah for a couple years

What I found is the static thrust is great with no ducting...gets off the ground fast, climbs up hill great. Down side is you left off the throttle and it feels like the brakes are on. Also hate the fear of wondering what will get sucked into the fan
On my Cermark I lost two rotors from small pebbles sucked in... I believe tossed up by the gear

Full ducting the plane flies much better at reduced throttle and has more top end... if I left off the plane keeps gliding nicely.... no more fear of FOD from inside the plane

I will never fly an EDF without ducting again....

Following Stu's advice all my EDF's are taped up tight on all the ducting... I work hard to have an airtight duct from the inlet to the tail and as smooth a flow as possiable..... gains are huge in my opinion

Ok that confirms it. I will keep the lip on and just have the ducting go over top and then tape it down. Should work great. I just don't like how ugly tape is.

you dont really want it over the top of the lip. you want to slip it inside the lip so it is a straight shot

Originally Posted by turbonut

you dont really want it over the top of the lip. you want to slip it inside the lip so it is a straight shot

I can't imagine that would make a huge difference though would it? Last thing I would want is the ducting slipping off and entering the fan itself.

Maybe I should just dremel the dang thing off and be done with it. It's just so pretty...seems a shame...