Century Jets Sport Hawk
03-25-2006, 06:09 PM
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Century Jets Sport Hawk
My largish project for the winter is a Century Jets Sport Hawk. Since there are no airport runways to fly from in the area, an electric parkflyer power system seemed like the best choice
. The plane weighs 9 pounds 15 ounces currently with an Aeronaut TF-4000 120mm fan, Nue 1912/1Y motor, Hacker Master Series Acro 90 ESC and a 9S1P 3.2 AH Kokam battery pack. Later the pack will be swapped for a larger TP pack for more flight time.
The control system uses RDS rotatry drives on the flaperons and rudder with conventional short pushrods from the twin aft mounted elevator servo's. Retracts are Spring-Air with 5/32" wire main struts and a Eurokit sprung nose strut. The test flight went great today, video here http://www.rcgroups.com/forums/showa...hmentid=776448 . Sorry for the wobbliness, it took a whole bunch of "beeps" to trim the elevator in the three different flight mode positions! In the end I landed flaps up since the trim with flaps down wasn't quite fine tuned - it'll land much slower on later flights...
. The plane weighs 9 pounds 15 ounces currently with an Aeronaut TF-4000 120mm fan, Nue 1912/1Y motor, Hacker Master Series Acro 90 ESC and a 9S1P 3.2 AH Kokam battery pack. Later the pack will be swapped for a larger TP pack for more flight time.The control system uses RDS rotatry drives on the flaperons and rudder with conventional short pushrods from the twin aft mounted elevator servo's. Retracts are Spring-Air with 5/32" wire main struts and a Eurokit sprung nose strut. The test flight went great today, video here http://www.rcgroups.com/forums/showa...hmentid=776448 . Sorry for the wobbliness, it took a whole bunch of "beeps" to trim the elevator in the three different flight mode positions! In the end I landed flaps up since the trim with flaps down wasn't quite fine tuned - it'll land much slower on later flights...
04-05-2006, 06:04 PM
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RE: Century Jets Sport Hawk
Chris,
I am just about to buy a Sport Hawk with the same setup as yours but using 10s3p at 6000 mah batteries. I'm concerned that I can fit three Battery packs in the plane. two 3s and one 4s. I'm doing this because I already have the two 3s batteries. Please comment on the fit and what you think of the planes performance. Neil
I am just about to buy a Sport Hawk with the same setup as yours but using 10s3p at 6000 mah batteries. I'm concerned that I can fit three Battery packs in the plane. two 3s and one 4s. I'm doing this because I already have the two 3s batteries. Please comment on the fit and what you think of the planes performance. Neil
04-05-2006, 06:12 PM
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RE: Century Jets Sport Hawk
What motor will you be using and what brand batteries are they - in other words, how thick are they?
The one modification I did was to make a series of scissor cuts about 3 or 4" long every inch around the duct then squeezed it down to the 120mm fan diameter / Ca'd / ran a glass bandage around the edge and filled the overlaps inside the duct. With that my 3S4P Thunder Power packs fit nicely between the fuse side and the fan. I have some other packs - Commonsence RC 3S3P which are thicker than the TP's, they are a very snug fit. The 4S pack can go on top for the fanprojecting forwards for balance.
LOVE the way it flies, really performs well. No the I have it fully trimmed out and doing aerobatics I'll have to shoot another video.
The one modification I did was to make a series of scissor cuts about 3 or 4" long every inch around the duct then squeezed it down to the 120mm fan diameter / Ca'd / ran a glass bandage around the edge and filled the overlaps inside the duct. With that my 3S4P Thunder Power packs fit nicely between the fuse side and the fan. I have some other packs - Commonsence RC 3S3P which are thicker than the TP's, they are a very snug fit. The 4S pack can go on top for the fanprojecting forwards for balance.
LOVE the way it flies, really performs well. No the I have it fully trimmed out and doing aerobatics I'll have to shoot another video.
04-06-2006, 01:23 AM
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RE: Century Jets Sport Hawk
chris,
do you belong to the pax club?.....in the early 90's i flew my ducted fans at webster field every weekend....then i got moved onto the main base and flew on the taxiway right by the hush house.....then 9/11 happened and nobody flew models there anymore due to the tightened security....i would love to get back on webster field to fly again....best place on earth to fly jets......
chris, i would love to pick your brain about the electric jets.....i'd like to try one, but i'd like to talk to an experienced person first before i ventured into this segment of the hobby.....
[email protected]
thanks,
richard
do you belong to the pax club?.....in the early 90's i flew my ducted fans at webster field every weekend....then i got moved onto the main base and flew on the taxiway right by the hush house.....then 9/11 happened and nobody flew models there anymore due to the tightened security....i would love to get back on webster field to fly again....best place on earth to fly jets......
chris, i would love to pick your brain about the electric jets.....i'd like to try one, but i'd like to talk to an experienced person first before i ventured into this segment of the hobby.....
[email protected]
thanks,
richard
04-06-2006, 05:03 AM
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RE: Century Jets Sport Hawk
You bet, that video was taken at our club field - Hellwig Field. Not sure what the deal is with flying on the base, I don't think anyone does it any more and it hasn't been a generally available thing to the club for years. Although we did do a couple of indoor sessions this winter at the TPS hangar which was cool. Be happy to talk to you - truercflyerATMSNdotCOM
04-06-2006, 09:18 AM
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RE: Century Jets Sport Hawk
Thanks for the response. I need to build my confidence that the batteries I have on hand will fit. I have two Thunder Power 6000mah 3s3p's...1 7/8" wide, 15/16" high and 7 3/4 long. I'll have to buy a 4s3p. It will probably be the same size but 2 1/2" longer. Three batteries total. I have'nt bought anything yet but so far, your comments are very helpful. The motor and ESC I plan to use are the same as yours but it was sugested that I use a Wemotec HW- 750 fan. Comments? Since your batteries fit on the side of the fan, and you narrowed the duct to fit, maybe I should do the same fan as you to be sure my batteries fit. What mah batteries do you use and what is your flight duration? I have another Fan jet using a .91 engine and I'm always concerned that the engine will quit. This problem goes away with an electric. This sounds like a real nice plane. I'm really looking forward to flying it.
04-06-2006, 09:59 AM
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RE: Century Jets Sport Hawk
I use 3 3S4P 8.0 AH TP packs, your packs are thinner so it shouldn't be a problem. The 750 is a 125mm fan and out of production, soon to be replaced by a new 120mm version in the next month or two from what I hear. If you find the old style 125mm 750 the correct motor to use with your battery would be the Nue 1910/1.5Y. My 1912/1Y is much too hot for a 10S3P pack. It works pretty well on 9S4P but even then it is a lot of amps
close to 90!
My first few flights were with a 9S1P pack of Kokam 3.2 cells, they effectively deliver about 2.5 AH and fly the plane for 3 minutes or so. The pack is only 2 pounds so the plane was light @ 10 and makes the first landing easier.
I flew it last weekend for the first time with the big 9S4P 8.0 AH Thunder Power packs. I flew for 6 minutes and used a little over 1/2 capacity. You could do 7 to 8 minutes of fairly hard flying max, or if you are just flying around at 1/2 throttle all the time it would go well over 10 minutes. With this pack the plane is 11 pounds 3 ounces, power is up several hundred watts so it flies just as well but longer. Landings are slightly different with the extra pound and a 1/4 but not bad.
close to 90!My first few flights were with a 9S1P pack of Kokam 3.2 cells, they effectively deliver about 2.5 AH and fly the plane for 3 minutes or so. The pack is only 2 pounds so the plane was light @ 10 and makes the first landing easier.
I flew it last weekend for the first time with the big 9S4P 8.0 AH Thunder Power packs. I flew for 6 minutes and used a little over 1/2 capacity. You could do 7 to 8 minutes of fairly hard flying max, or if you are just flying around at 1/2 throttle all the time it would go well over 10 minutes. With this pack the plane is 11 pounds 3 ounces, power is up several hundred watts so it flies just as well but longer. Landings are slightly different with the extra pound and a 1/4 but not bad.
04-06-2006, 11:37 AM
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RE: Century Jets Sport Hawk
Sure it does, that and the 1910/1.5Y are roughly = except for price
Attached are some pics of Hoser's plane!
And here is a link to a short landing clip http://static.rcgroups.com/forums/at...IiWGWToKOyMj==
Attached are some pics of Hoser's plane!
And here is a link to a short landing clip http://static.rcgroups.com/forums/at...IiWGWToKOyMj==
04-19-2006, 05:17 AM
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RE: Century Jets Sport Hawk
Chris,
I finally received my Century Sport Hawk kit and the plans are inadequate for me. The wing mount is a prior design drawing and doesn't show the aluminum bar and C section. I did get the bar and C section in the kit. I see from your build log photo that you cut the wing to insert the bar. Please explain the installation. Did you reinforce? I got a bunch of laser cut pieces in the kit but I don't see any location info on the plan other than the servo mounts. Does this model need internal reinforcement sections? Also, how did you do the exhaust tube from the fan? I bought a Neu 1912-1Y motor and a HW750 fan with a 19s battery and a Hacker 90 ESC. Most of that design I got from your messages on RC Universe. Last question (for now), You installed flaperons in your plane. I'm not an expert flyer although I do have a 91 powered ducted fan that I fly and I really need the slow speed for landings. Do you think I need flaperons? How about adding flaps? I obviously need help with this kit so I would appreciate all I can get. Thanks, Neil
I finally received my Century Sport Hawk kit and the plans are inadequate for me. The wing mount is a prior design drawing and doesn't show the aluminum bar and C section. I did get the bar and C section in the kit. I see from your build log photo that you cut the wing to insert the bar. Please explain the installation. Did you reinforce? I got a bunch of laser cut pieces in the kit but I don't see any location info on the plan other than the servo mounts. Does this model need internal reinforcement sections? Also, how did you do the exhaust tube from the fan? I bought a Neu 1912-1Y motor and a HW750 fan with a 19s battery and a Hacker 90 ESC. Most of that design I got from your messages on RC Universe. Last question (for now), You installed flaperons in your plane. I'm not an expert flyer although I do have a 91 powered ducted fan that I fly and I really need the slow speed for landings. Do you think I need flaperons? How about adding flaps? I obviously need help with this kit so I would appreciate all I can get. Thanks, Neil
04-19-2006, 06:56 AM
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RE: Century Jets Sport Hawk
Didn't you get the 26 page instruction manual? To install the aluminum sparsyou cut the slot then add 1/8" balsa extension top and bottom which are tall enough to reach above the wing sheeting. Mask off all around the slot on the sheeting so the glue doesn't run all over the place, liberally coat everyhting with epoxy and slip the spar+ extensions in the slot. Prop everything up for the correct dihidreal and let it cure. Once the epoxy has set but isn't rock hard remove the tape and the glue overflow. Let it set hard then sand the balsa extensions even with the wing. No further reinforcement is needed.
Give me a few more weeks of flying it to come to a conclusion on the no flaps / flaperon / flaps question. Hoser flies his with no flaps and it does OK so it may not be totally necessary. I'm happy with how mine hanldes so far - that first landing was WAY faster than it lands now either flaps up of down! It does need a whole bunch of up elevator mixed in with flap deployment though.
The only ply formers I used is the egg-crate front retract mount and servo mount assembly which is about 11 pieces and the one ply former that is a bout 2" high that the C-section spar receptacle mount to. No other formers needed except the rudder spar of course. You want the put a little wood at the rear of the hatch where the dowels holes are drill though. I didn't use any of the motor mount pieces. I've got a ring on my fan which bears against the edge of the inlet duct for thrust loads and just a single screw that bolts the ring to a hunk of hardwood glued on the inlet which keeps the fan from falling out to the rear. The thrust tube is made from thin mylar sheet and masking tape.
Give me a few more weeks of flying it to come to a conclusion on the no flaps / flaperon / flaps question. Hoser flies his with no flaps and it does OK so it may not be totally necessary. I'm happy with how mine hanldes so far - that first landing was WAY faster than it lands now either flaps up of down! It does need a whole bunch of up elevator mixed in with flap deployment though.
The only ply formers I used is the egg-crate front retract mount and servo mount assembly which is about 11 pieces and the one ply former that is a bout 2" high that the C-section spar receptacle mount to. No other formers needed except the rudder spar of course. You want the put a little wood at the rear of the hatch where the dowels holes are drill though. I didn't use any of the motor mount pieces. I've got a ring on my fan which bears against the edge of the inlet duct for thrust loads and just a single screw that bolts the ring to a hunk of hardwood glued on the inlet which keeps the fan from falling out to the rear. The thrust tube is made from thin mylar sheet and masking tape.
04-19-2006, 07:20 AM
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RE: Century Jets Sport Hawk
Chris , Thanks for the response. No, I didn't get a 26 pg instruction manual. I was led to believe that their was no more info. Thanks, I'll call them and get it. Neil
04-23-2006, 03:39 PM
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RE: Century Jets Sport Hawk
Chris, I got the instructions and I'm building. I'm almost ready to mount the wings and I'm concerned that I have the correct wing angle of incidence. Do you know what It should be? If so please send me a note. Thanks, Neil
04-26-2006, 07:43 AM
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RE: Century Jets Sport Hawk
Thanks to both of you. I've been in this sport only 8 years and the second strike against me is that I'm 74 years old. I fly a ducted fan with a .91 engine and I'm anxious to fly the electric. (my 2nd electric). I have read Chris's build log and many photos. They are a big help. Now that I got the instructions, plus the info from Chis, I think I am OK. However, I would really like whatever photos you can send me. I'm sure it will help. The plans from Century are for the non electric version and I could use photos in those areas as well as installation of the wing spar joiner. Neil
05-11-2006, 02:25 PM
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RE: Century Jets Sport Hawk
Chris,
I am coming along well on my Hawk. Have the wings and stab installed. I have a few questions on the fan. I have a 4000 fan which looks like yours in the build photos. The fixed fan blades are attached to the motor enclosure but are not attached to the outer fan enclosure. I plan to epoxy the fixed blades to the outer duct
fan enclosure with the fixed blades at the end of the duct. This leaves plenty of room for the rotating blades within the duct. Any comment? Also, it appears that you did not secure the fan duct to the fuse. How did you support the fan/motor assembly? Neil
I am coming along well on my Hawk. Have the wings and stab installed. I have a few questions on the fan. I have a 4000 fan which looks like yours in the build photos. The fixed fan blades are attached to the motor enclosure but are not attached to the outer fan enclosure. I plan to epoxy the fixed blades to the outer duct
fan enclosure with the fixed blades at the end of the duct. This leaves plenty of room for the rotating blades within the duct. Any comment? Also, it appears that you did not secure the fan duct to the fuse. How did you support the fan/motor assembly? Neil
