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RV-3B G-HILI (Andy & Ellie Hill)

Andy Hill

Well Known Member
Whilst this thread specifies "Build Project", and G-HILI has flown - the other section is for "finished RVs". At this point, G-HILI might fly but is far from finished :eek:

I shall try to make single posts for particular areas / aspects, and then amend those posts as and when things progress / change.

Basics:
  • Emp Kit ordered Apr 2009
  • 1st Flight 15 Jun 2015
  • Basic Weight / Index: 733lbs / 57.59"
  • IO-320-B3B (Narrow Deck) rebuilt from vandalised Apache - in fact parts from each engine :cool:
  • MTV-11 2 blade VP Prop (72")
  • Full Inverted Oil & Fuel
  • Built for lightweight fun ;)
(as at 20 Jun has done 7 flights, 2:45 TT)
 
Seat / Harnesses

RV3Seat.jpg


The seat 'cushions' are made from 'Minicel' foam - a lightweight closed cell foam used in Kayak seats apparently ;) 2lbs / ft3 :D Comes in various shapes & sizes:
  1. It is a little "firm" as a direct seat cushion
  2. You can cut (Bandsaw/Knife), shape (sandpaper, electric sander) and glue the material as you wish
  3. Works well with no further covering / finish, if a little unsightly i.e. does not abrade / flake off.
The (deep) seat base cost ~$30, the seat back $20 inc shipping :eek: Each has only a few hours invested work to date... The seat base weighs 13oz, the seat back 10oz!

Currently I am flying with a parachute, and use the seat base only. Without a chute, the seat back is fine (but firm).

Likely progress would be:
  1. With Chute: a much thinner seat back (1/2"?) with raised edges to stop back sliding about
  2. Without Chute: A single added layer of softer foam / sheep skin like (?) for looks / comfort
Harnesses are 5pt Crow with 'Latch and Link' (lighter and less bulky than Kam Lock ;) ). The negative 'g' attach point is own design - not in the RV-3 plans (a common theme).

Overall, for not a lot of time in design and fabrication, a very comfortable seating position so far, and just takes a sander to refine. And above all, lightweight...
 
Andy,

I'm guessing that your Minicel foam is most likely what we call Ethafoam on this side of the pond. Great for building up seat thickness, but a bit firm for us sissies.

Used it on my Panther seat with good success.

Tony
 
Andy,
Thanks for the seat material tips. Your lightweight plane has motivated me to put mine in a diet. I've identified about 20 pound a I can easily shed. I think I'm going to make a lightweight seat for local flying and I'll use my plush normal seat for cross country flights.
 
Seems similar Tony, and as you say, needs a softer top layer ;)

Glad to persuade you Rob :) There is lots of potential...
 
Electrical System

G-HILI is a lightweight "Day VFR" fun machine. The electrical system comprises:
  • Low Capacity (14AH) battery
  • B&C SD-8 Alternator & Regulator (on Vacuum Pad)
  • No relays - Batt Master directly supplies fusebox, Starter pb directly supplies Starter Solenoid (see B&C 'Aerobatic Aircraft' circuit diagram)
  • No External or Internal lighting
  • Andair Electric Fuel Pump
  • Skytec XLT starter 4awg cable
  • To provide some redundancy, there is a Battery Isolator (mechanical switch)
The SD-8 has proved adequate even with ~20min flights and battery being charged enough in flight for next start.

Any comments or potential hazards / weaknesses would be appreciated. It has worked well over the 1st 16hrs or so...
 
W&B Limits

As above:
?Basic Weight / Index: 733lbs / 57.59"

After some minor adjustments (add 1lb VHF, removed 3lb blue plastic, add 2lbs Inverted Oil pipes) now:
?Basic Weight / Index: 733lbs / 57.46"

RV-3B limits are:
  • MTOW 1100lbs (Vans) / 1175lbs (UK LAA approved limit)
  • Max Aerobatic AuW: 1050lbs
  • Fwd CG: 59.72"
  • Aft CG: 64.58"
  • Aft Aerobatic CG: 63.5"
Max AuW: Max Pilot (200lb - would not get much more in this RV-3), Max Fuel, Max Baggage:
1163lb / 64.03" Inside MTOW and Aft CG, Outside Aerobatic Wt/CG

For Aerobatics with nil baggage:
200lb Pilot, 1/2 Fuel: 1023lb, 62.15" Inside Aerobatic Wt & Cg limits
185lb Pilot, 2/3 Fuel: 1038lb, 61.77" Inside Aerobatic Wt & Cg limits

Assuming a 25lb Smoke System added as 'Baggage' Display W&B:
185lb Pilot, 1/2 Fuel: 1033lb, 63.10" Inside Aerobatic Wt & Cg limits

Anticipating Paint will add 15lbs and move CG aft a little - albeit 1.5lbs can be taken off tailwheel/fork to compensate - still leaves above scenarios in limits.

(The Test Flying program has been completed, and flown in various Weight/CG Configurations, and no observations were made to contradict the above calculations)
 
Engine / Prop

Engine
Lycoming IO-320-B3B which strictly does not exist :eek:

It is a "Narrow Deck" engine (I am led to believe is 10-15lbs lighter than a more modern Wide Deck?) from a 1960 :confused: Piper Apache (which was vandalised :( ) - G-HILI's engine was rebuilt using components from each of the Apache's O-320-B3B engines.

It was rebuilt / equipped with:
  • Conical Engine Mount
  • 2x P-Mag
  • Sky Dynamics Intake / Sump / Lightweight Exhaust / Featherweight Flywheel (Horizontal Induction)
  • Silverhawk FI Unit
  • Skytec XLT Starter
  • B&C SD-8 Alternator on Vacuum pad
  • Earls 20700 Oil Cooler
  • 'Standard' aft facing Oil Filter fitting (goes into Firewall cutout)
  • MT Governor
  • (Full) Raven Inverted Oil system
The low Basic Weight of this RV-3 I believe is largely down to the Engine / Ancillary spec - there are many lbs to be saved if one can avoid an "off the shelf" engine spec.

Prop
MT MTV-11-C/183-59 - this is the lightest VP prop we could fit, whilst meeting the UK effective requirement of being 'certified' (quoted as 35lbs inc spinner)
 
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