Thread Tools
Oct 15, 2019, 03:18 PM
Registered User
That's really smart but the Colonel's smart too - I also am agog.
Sign up now
to remove ads between posts
Oct 17, 2019, 06:48 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Thread OP
Well, what a goshdarn coincidence, I do declare............. because I am intending to do EXACTLY what George explained, as it keeps the joiners straight, and keeps the centre section below the strip stock length of 36".............. ahem, yup.........

<Runs off and fires up the CAD, whilst simultaneously cancelling the order for 48" balsa........>

Oct 17, 2019, 11:07 AM
'Douglas' to his friends.
Yep..! Smart, alright, that there CB..!
Oct 17, 2019, 01:44 PM
I like real wooden aeroplanes!
Sundancer's Avatar
Well, there you go Colonel. Verification of the old proverb "Great minds think alike". We won't mention the fact that for every proverb there is always a contrary one, in this case "Fools never differ"!!
Oct 20, 2019, 08:16 PM
Registered User
Hi Colonel, good to see progress being made, look forward to the finished project. Any idea of timing? I know it is Autumn in the Isles so maybe no need for haste. I have completed my version and am now waiting for the spring winds and rain to b***** off. I also had an Airsail Ascender that was rubber powered free flight and suffering severe hanger rash on the tissue so have recycled that as well. Recovered in Solarfilm "Solite", fitted an 1811/2000 outrunner with a folding prop from an old Flyzone "Ventura". Model weighs 8 grams less than rubber powered. The 2g servo came from a "Deleted" Hobby King Von Stik micro flyer.
Oct 21, 2019, 05:03 AM
I like real wooden aeroplanes!
Sundancer's Avatar
I have to admit that I never thought I would see a KK Invader with "sharks tooth" nose decor!!! But then again, all those years ago (1947) when I built my original I never expected to ever see a ducted fan powered one with twisty wing R/C!! Eagerly awaiting news of the test flights!!
Oct 21, 2019, 06:29 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Thread OP
Yup, I like that a lot - nice colour scheme! Although I share George's surprise concerning the 'sharks teeth', I must admit it doesn't look too out of place! And although what I know about DFs could be written on the head of a 1/10 scale pin, it may be worth inserting a paper tube into said shark's mouth to smooth the airflow into the fan - I understand that turbulence (from structure and wires) on the intake side can play havoc with thrust on the effluent side.

Nice save on the Ascender too!!!
Last edited by Colonel Blink; Oct 22, 2019 at 01:21 AM. Reason: spelingg
Oct 21, 2019, 10:07 AM
Registered User
I found the intake (in the pics), but couldn’t locate what the Colonel so elegantly calls the ‘effluent side’ (site?)...
Oct 21, 2019, 01:47 PM
Registered User
For sure you need a duct before and after the fan (high speed air don't like the obstructions to the flow).
I have a Mistral (Vampire for the RAF); at start I had a fan with scale entries with poor front duct (too much turn to arrive to the fan in the middle of the fuse).

The performance was miserable (catapult start), the Mistral was just flighing with no vertical possibility ; inacceptable for a fighter!
So I replace the fan with a prop; and now I have splendid fighter in the air.

Guy
Oct 21, 2019, 07:39 PM
Registered User
Hi K K, refer to posts #55 and #74. It shows the hole in its bottom/rear where all the "effluent" (efflux) exits..
Oct 22, 2019, 01:14 AM
Registered User
Thank you all for your observations, I shall take it all on board. I will retry the model in flying form on my test bench to confirm thrust etc. The total FSA (fan swept area) is 1421 sq/mm equating to approx 48 mm dia. The effluent? efflux/ tailpipe is 43 mm dia, approx 88% of fan dia. Nose intake is approx 105% of fan dia. you will note that the wiring is fairly well out of the airstream showing above photo. The wires hanging down will be out of the draft when all is ready to run, the only thing that will show is the ESC on the stbd side. The all up weight is (with battery inside the top hatch) 360g (12.7oz) giving 5.97 oz/ftsq and a thrust of 254g (9oz). Power is 142 watts lb. I will try a tube in the intake to see if there is any improvement.
Oct 22, 2019, 01:26 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Thread OP
360g AUW / 254g thrust? With a power to weight ratio of 0.7:1 it should fly absolutely fine! I think I remember reading somewhere that 0.3 was Ok for a 'powered glider' and 0.5 could fly a 'normal' model............ or did I simply dream that??

Oh yes and of course 'efflux' is the correct word, rather than effluent....!!
Oct 22, 2019, 01:34 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Thread OP
And just to prove that although slow, some progress has been made..... I haven't been completely sitting on my thumbs!
Oct 25, 2019, 02:39 AM
So I'M meant to be in control?
Colonel Blink's Avatar
Thread OP
Mmmmmm......stringers! I really must build a Mamselle at some point.....
Oct 25, 2019, 06:03 PM
I'd rather be flying.....
JeffMac's Avatar
Looking really nice CB......

Best regards,

Jeff


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log RDBO 2018 KeilKraft Ace x 1.5 (45") - Now CAP 2018! Colonel Blink Vintage & Old-Timer Designs 128 Sep 19, 2018 07:05 PM
Careful! Hillary's Ear Doctor: At The Next Debate Scan And Record Her Ear Coach! traceyl Life, The Universe, and Politics 5 Sep 09, 2016 04:59 PM
Build Log KeilKraft Pixie Mega. fuzzypaul Giant Electric Planes 19 Oct 02, 2015 03:22 PM
Discussion What is it about slope that just keeps me smiling ear to ear?! Admiral_Red Slope 19 Jul 22, 2006 06:18 PM
Rave I'm Grinning Ear To Ear PGR Slope 0 Mar 18, 2006 09:42 PM