How to use this R66 W&B calculator
- Enter the empty weight, longitudinal arm and lateral arm from your aircraft's weight and balance record. The defaults are the POH sample values only.
- Choose your units: lb or kg for weights, inches, cm or metres for arms, and US gallons, litres, lb, kg or percent for fuel.
- Type or slide the weight of the pilot, four passengers, under-seat baggage and the main baggage compartment, plus anything on the accessory mount bars.
- Set your fuel, at the POH figure of 6.7 lb per US gallon of Jet A.
- Tick any configuration changes such as doors removed or left seat controls out, and add an external load if you are flying with the cargo hook.
- Check the status box and the two CG envelope charts. The filled dot is takeoff weight, the hollow dot is zero fuel weight, and the line between them shows how the CG moves as you burn fuel. Green means inside limits, red means outside.
- Hit Print or save as PDF for your flight folder, or jump to the R66 hover ceiling calculator with your takeoff weight already filled in.
R66 weight and balance limits
These are the figures the calculator uses, shown in the units you selected above. They are taken from Section 2 (Limitations, CG envelope FAA approved 6 Jul 2018), Section 6 (Weight and Balance, revised 23 Dec 2022) and the Cargo Hook Equipment Supplement (FAA approved 6 Jul 2018) of the Robinson R66 Pilot's Operating Handbook, but the POH for your specific aircraft and serial number is always the authority.
| Limit | R66 |
|---|---|
| Maximum gross weight | 2700 lb (1225 kg) |
| Minimum gross weight | 1400 lb (635 kg) |
| POH sample empty weight | 1290 lb @ 109.00 in |
| Forward CG limit | 91.00 in up to 2500 lb, then 92.00 in at 2700 lb |
| Aft CG limit | 102.50 in up to 2300 lb, then 98.00 in at 2700 lb |
| Lateral CG limit | 3.50 in left to 3.50 in right at the widest point, narrowing towards the ends of the envelope (see chart) |
| Usable fuel | 73.6 US gal, about 493 lb of Jet A at 6.7 lb per US gal |
| Seat limit | 300 lb (136 kg) per seat including the baggage compartment under it |
| Baggage compartment | 50 lb (23 kg) in any under-seat compartment. Main baggage compartment 300 lb (136 kg) total, 50 lb per square foot |
| External load (R66) | 1200 lb at 90.80 in, 2900 lb combined (cargo hook supplement, FAA approved 6 Jul 2018) |
| Reference datum | 100.00 in forward of the main rotor shaft centreline |
R66 Turbine station arms
| Station | Longitudinal arm (in) | Lateral arm (in) | Limit |
|---|---|---|---|
| Pilot (front right) | 49.00 | +12.20 (right) | 300 lb |
| Baggage under pilot seat | 42.00 | +12.20 (right) | 50 lb |
| Front left passenger | 49.00 | -12.20 (left) | 300 lb |
| Baggage under front left seat | 42.00 | -12.20 (left) | 50 lb |
| Aft right passenger | 80.00 | +16.00 (right) | 300 lb |
| Baggage under aft right seat | 82.00 | +15.00 (right) | 50 lb |
| Aft centre passenger | 78.00 | 0.00 | 300 lb |
| Aft left passenger | 80.00 | -16.00 (left) | 300 lb |
| Baggage under aft left seat | 82.00 | -15.00 (left) | 50 lb |
| Baggage compartment | 107.00 | 0.00 | 300 lb |
| Accessory mount bar, right | 23.00 | +14.00 (right) | see seat limit |
| Accessory mount bar, left | 23.00 | -14.00 (left) | see seat limit |
| Fuel tank (Jet A) | 102.50 | -3.00 (left) | 73.6 US gal |
| Left seat controls removed | 31.00 | -13.00 (left) | -2 lb |
| Front right door removed | 49.50 | +26.80 (right) | -8 lb |
| Front left door removed | 49.50 | -26.80 (left) | -8 lb |
| Aft right door removed | 75.20 | +27.20 (right) | -7 lb |
| Aft left door removed | 75.20 | -27.20 (left) | -7 lb |
How the R66 weight and balance calculation works
Every item in the helicopter has a weight and an arm (its distance from the datum). Multiply them and you get a moment. Add up all the weights and all the moments, divide total moment by total weight, and the result is the centre of gravity. The calculator does this twice: once longitudinally (fore and aft) and once laterally (left and right), because the R66 has limits in both directions.
It also works out two loading conditions. Takeoff weight includes fuel. Zero fuel weight is what you would weigh with the tank empty. The R66 tank sits at 102.5 in, behind the CG, so burning nearly 500 lb of Jet A moves the CG forward by an inch or more over a long flight. The POH envelope even marks the most forward CG you can accept with full fuel and still be in limits at zero fuel. The line between the two dots on the chart shows that movement, and both ends have to stay inside the envelope.
Five seats and a 300 lb baggage compartment at 107 in give the R66 a wide loading range. Three heavy passengers in the back with a full baggage compartment push the CG aft; a solo light pilot with no baggage pushes it aft too, because the empty CG is already at about 109 in. The lateral case matters with the aft centre seat empty and one side loaded.
R66 weight and balance FAQ
What is the maximum gross weight of a Robinson R66?
The R66 has a maximum gross weight of 2,700 lb (1,225 kg) and a minimum of 1,400 lb (635 kg). With the factory cargo hook the combined weight of helicopter and external load may go to 2,900 lb (1,315 kg), but anything above 2,700 lb must be jettisonable load and the landing gear is still limited to 2,700 lb. Each seat is limited to 300 lb (136 kg) including the compartment under it, each under-seat compartment to 50 lb (23 kg), and the main baggage compartment to 300 lb (136 kg) at no more than 50 lb per square foot.
What are the R66 CG limits?
The longitudinal CG must stay between 91.0 and 102.5 inches (231 to 260 cm) aft of datum. The forward limit tapers from 91.0 in at 2,500 lb to 92.0 in at 2,700 lb, and the aft limit from 102.5 in at 2,300 lb to 98.0 in at 2,700 lb. With an external load the envelope extends to 2,900 lb between 92.0 and 100.5 in. The lateral CG limit is 3.5 in (8.9 cm) left or right, reducing to 2.5 in (6.4 cm) at the aft end. The datum is 100 inches forward of the main rotor shaft.
How much fuel does an R66 hold?
The single bladder tank holds 74.6 US gallons, of which 73.6 US gallons (279 litres) are usable. Jet A weighs 6.7 lb per US gallon in the POH loading calculations, so full fuel is about 493 lb (224 kg). The tank sits at 102.5 in, aft of the CG, with a lateral arm of 3.0 in left, so burning fuel moves the CG forward and slightly right.
What is a typical R66 empty weight?
The POH sample calculation uses 1,290 lb (585 kg) at 109.0 in with a lateral moment of 431 in-lb (0.3 in right). Your aircraft will differ depending on installed equipment, so always use the empty weight and CG from your aircraft's own weight and balance record.
Can a light pilot fly the R66 solo?
Section 2 of the POH says that with all doors installed and nothing in the baggage compartment, a solo pilot of 160 lb (73 kg) or more will keep the CG within limits. Below that you must compute weight and balance and may need removable ballast to bring the CG forward of the aft limit. Try it here with a light pilot and no baggage.
How do I do weight and balance with the R66 cargo hook?
Tick External load in the configuration section and enter the load. The hook is at 90.8 in with a lateral arm of 4.1 in left, per the cargo hook supplement, and the calculator checks the loaded case against the 2,900 lb external-load envelope, which is drawn dashed on the chart. The unloaded case is still checked against the normal envelope, because you have to be legal after you release the load.
Does this calculator work in kilograms and centimetres?
Yes. Switch weights between lb and kg, arms between inches, centimetres and metres, and fuel between US gallons, litres, pounds, kilograms and percent. The whole page, including the envelope chart axes and the reference tables, updates to the units you pick.
Is this R66 weight and balance calculator free?
Yes. It runs entirely in your browser, needs no account, and you can print or save your result as a PDF. The station arms and limits are taken from the R66 POH Sections 2 and 6 and the cargo hook supplement, and the calculator reproduces the POH sample loading calculation exactly. If you want to save aircraft profiles, sign your W&B, email it and see hover ceilings live in flight, download the free Tool in the Cockpit app.
