Thread Tools
May 27, 2020, 06:33 AM
Registered User
Thread OP
Build Log

Big prop, low RPM biplane: the HV F.1

Construction has begun on a WWI-style biplane.

Span 100 cm
Length circa 80 cm
Wing area 41 dm^2
Weight around 1 kg (I hope to end up around 800 g, but 1 kg might be more realistic...)
T-Motor 3515 400 kv motor
50A red brick ESC (Might get substituted for something quite a bit lighter, but I have this already...)
2s 1600 mah battery
16x16 Fiala propeller (With ground clearance enough to go to an 18" prop if necessary)
Last edited by IridiA; May 27, 2020 at 06:34 AM. Reason: Correcting data
Sign up now
to remove ads between posts
May 29, 2020, 07:00 AM
Registered User
Thread OP


Tried 60mm stainless steel m4 bolts as standoff, I reckon it will be more than stable enough...
May 29, 2020, 07:07 AM
Registered User
Thread OP
Revised drawing:

Nose shape changed from round cowl to Sopwith Tabloid-esque shape
Interplane distance increased
Landing gear lengthened
Struts moved further outboard
May 29, 2020, 07:56 AM
Registered User
Look OK
Any inter plane rigging?
I would be rather concerned at such long M4 stand offs. Never convinced using stand offs is structurally a good idea. Why not build the fuselage forward to a bulkhead to pick up the motor mounts directly?
May 29, 2020, 08:32 AM
Registered User
Thread OP
I thought I'd need an extra bulkhead as well, but after tugging a bit on the standoffs I'm not so sure, it feels really solid.

I'm certain the wings will hold by themselves, but for good measure (and good looks) I will add functional rigging, both flying and landing wires. This will also give me the means to put in a small amount of dihedral if the need arises.
May 29, 2020, 02:42 PM
Registered User
Thread OP
One unsolved problem is how to actuate the ailerons on the top wing (the bottom wing will have no ailerons). The wing is a bit too thin for 9g servos to fit flush, and I think a pull-pull setup would fit the style of airplane well. But how do you do pull-pull ailerons simple?
Jun 04, 2020, 03:02 PM
Registered User
Thread OP
Adding a forward bulkhead to mount the motor directly without standoff. Using plywood spacers to align it with the rear bulkhead, these spacers will later be glued in as reinforcement as the fuselage sides are only 5 mm XPS and the motor + prop is over 200 g. Both bulkheads are 1 mm plywood which is quite flimsy but reinforced with 6x6 mm pinewood and built into a box structure its sturdy enough.
Jun 06, 2020, 10:29 AM
Registered User
Thread OP
Gluing in the strut mounting tabs before doing the rear landing gear struts, this way the wing can be placed flush on a table while working which makes it easier. Using PU glue with slots cut all the way through the wing and tape on the underside to prevent the glue from foaming out there, the tabs are pushed down until they sit against the tape.
Jun 17, 2020, 04:09 PM
Registered User
Thread OP

Red Brick

Soldered connectors to the Red Brick 50A ESC today and attempted to program it. I found at least 3 different manuals online for ESCs if this name, neither which fully matched the behaviour of mine...
I quickly decided to use the RB for some future 1-hour build instead where I can chance not having a clue how voltage cutoff is configured, and instead ordered a 30A ZTW Beatles with matching programing card.
Jun 17, 2020, 04:12 PM
Registered User
Thread OP


Does anyone know a source of ~100 mm (4") vintage-style wheels that don't weigh a ton and cost as much as the rest of the hardware in the airplane put together?
Jun 18, 2020, 03:03 PM
Registered User
Thread OP
Ailerons mounted

Quick Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Bixler 1.1 Low KV big prop daz23 Electric Plane Talk 0 Nov 24, 2014 05:24 AM
Discussion Large, low pitch prop at higher RPM or Smaller high pitched prop for efficiency? RS2K Power Systems 1 Sep 19, 2014 09:24 AM
Help! Big prop, high pitch, low rpm, low voltage invertmast Power Systems 16 Dec 25, 2011 11:38 PM
Question Which is better - low RPM and big prop or vice-versa ikorman Electric Plane Talk 18 Nov 15, 2009 05:57 AM
Big prop-low rpm or small prop-high rpm Ninjak2k Power Systems 10 Feb 13, 2002 05:28 PM